Heating system Model S

[Milzit]

Hello
I´m living in Norway and we are considering to make a reservation for Model S. Do anybody have any information about the heating system or is that not ready yet? In a country like Norway you need heating in the winter.. It will just take the power from the battery?

[EV_de]

it's part of the Model-S-feature-wishlist (http://www.teslamotorsclub.com/showthread.php/2549-Another-Model-S-feature-wishlist).

together with remote controlled (pre) heating / cooling

[Cobos]

The Roadster uses electric heating and not a heatpump. That takes a bit of a bite out of the battery, so I hope they go with a heatpump system for the Model S. I also want a Webasto like diesel/oilbased heating system for cold climates, but I'm not sure if I'm getting that.

Cobos

[jkirkebo]

There should be no need for a Webasto (or similar) if they use a heatpump. 1.5kW for heating will give you a ~10% loss in mileage which for me at least is very acceptable. And I also live in Norway ;)

The newer heatpumps give good performance down to -20C and works down to -26C. There should of course be a resistance heater as backup.

[eledille]

Some of us need to cross the mountains in the winter. That sometimes means waiting for snow clearing equipment for hours in very low temperatures and high winds, so I certainly want a diesel heater. The lack of a diesel heater as an option is not a total showstopper, as one can be installed later on. But a factory installed unit would obviously be better and probably less expensive too.

I think they should go for a heat pump as standard and an additional diesel heater as an option. Burning off the power in a resistor is just silly when you can get at least three times as much heat for your electrons with a heat pump. Besides, air cooled resistance heaters burn dust. You want a water cooled unit, but that will probably cost more than a heat pump, as only minor modifications of the AC unit are needed (a few computer controlled valves and a reversible pump).

[PaulM]

I too have thought about the benefits of a fuel powered heater (gets cold in Canada). Some old VW Beetles had a gas heater since you didn't get much heat from the air cooled engine. Although I have not found one yet, a Webasto type heater which could run on a small propane tank (like the ones used for camping) would be ideal. Coleman makes a propane water heater for camping so it should be pretty easy to do (http://www.coleman.com/coleman/colemancom/detail.asp?product_id=2300B700).

However as jkirkebo indicated above, the new heat pumps have much better performance than in the past, the only problem is I don't think there are any suppliers building heat pumps in the automotive industry, only residential. Remember, 99.999% of current vehicles have more than enough waste heat to heat the cabin so why would anyone bother developing a heat pump, only a straight A/C is required. Tesla would have to design their own and I think they have enough on their plate already. GM designed a heat pump for the EV1 but they also spent a billion dollars on its development. Even Nissan went with resistive heater for the Leaf. (KISS)

I am told that a heat pump is simply an A/C running backwards so Tesla may be able to get an A/C supplier to modify their A/C unit to enable running as a heat pump but I don't know how efficient it would be. I am certain that all EV manufacturers will eventually go this route, I just don't know if it will be in the Model S version 1.0.

Another thing to consider is that the Model S motor will be liquid cooled and even if it is about 90% efficient, it will still generate quite a bit of heat. Having a heat pump extract heat from the coolant instead of from the air would be much more efficient.

[eledille]

Why propane? We have a diesel powered Webasto Air Top 2000 unit in our Think City which works just nicely. The same unit is available in gasoline, biodiesel and ethanol versions. It uses between 0.2 and 0.4 liters per hour and generates 1 to 2kW of heat. The difficulty is where to place the fuel filler neck and exhaust pipe. Think solved that by placing the tank and filler assembly behind the rear license plate, which is tilted upwards to get at the filler cap. If you plan to have the tank and filler inside the car I can understand the concern (diesel is messy), but then I think ethanol would be OK.

To get maximum efficiency from a combined A/C and heat pump unit, it needs a computer controlled choke valve that separates the high and low pressure parts of the system, a pump that will work in both directions, and a pump motor drive capable of many power levels in both directions. This is now less expensive than it used to be. Modifying an automotive A/C design to do this might be expensive, but then the Model S is a high end car, the "reduced range in cold weather"-argument shows up quite often, and the Model S will be made in much higher numbers than the roadster, though fewer than the Leaf. I don't know how it all adds up, but I hope for the best.

Toyota had a heat pump in their RAV4 EV, I believe, so Toyota has done it before. Anyway, as so many new electric vehicles are going to hit the roads in the next few years, I would have thought that some supplier would be interested in doing this.

If they end up with a resistive heater, then they really need to offer a fuel-powered unit.

I agree about extracting waste heat from the motor, but I think that that might be a bit challenging. If the battery, pem and motor are on the same cooling circuit they will need to make sure that the heat pump does not negatively affect the temperature of the battery. They might need sensors, multi-way valves and firmware to control the whole thing.

[araxara]

Now that some people actually have a Model S, I would think there would be more information available regarding the type of heating system used in the car. I can't find any information online. Maybe some here knows? If the Model S uses a heat pump, I would think that Tesla would like to advertise this. But their silence is starting to worry me.

[Jason S]

Heck, I can't tell ya how the heater works in any of the cars I've ever had. Where would I look in the manual?

[spleen]

I'm pretty sure that I've heard that it's a heat pump but can't find a confirmation online currently ...

[MikeK]

I've been told it's a resistive heater, which I found disappointing. I hope it's actually a heat pump.

[araxara]

I've been told it's a resistive heater, which I found disappointing. I hope it's actually a heat pump.I hope it's a heat pump too because if the resistive heat in the Nissan Leaf is any indication, winter range will get zapped considerably. From what I've heard, running modern refrigeration systems backwards to make them into heat pumps is not an issue.

[NigelM]

Now that some people actually have a Model S, I would think there would be more information available regarding the type of heating system used in the car. I can't find any information online. Maybe some here knows? If the Model S uses a heat pump, I would think that Tesla would like to advertise this. But their silence is starting to worry me.

Dude, you live in Tucson. This shouldn't worry you for one second.

[jerry33]

It's primarily a heat pump, but I believe there are also resistive heaters for extreme conditions. My understanding is that heat pumps aren't great when the temperatures are very cold (below 0 F). If you get the leather seating option, there are seat heaters. I don't know why they don't come with the cloth seats, because heated seats are very efficient (mainly because they let you set the main heating at lower temperatures or not use it at all.)

[araxara]

Dude, you live in Tucson. This shouldn't worry you for one second.It gets cold in Tucson in the winter time and we occasionally have snow. But I'm planning to travel to the White Mountains where it's properly cold (similar to New England). It's a 200 mile trip with a about a 4500ft elevation gain.

[NigelM]

It's a 200 mile trip with a about a 4500ft elevation gain.

That would worry me much more than the weather.

[araxara]

That would worry me much more than the weather.Yes, it's pretty close without the weather. I've used several "programs" to estimate if I can make it. The most complete I've found has been Green Race (http://jurassictest.ch/GR/).
9385

[mknox]

I've been told it's a resistive heater, which I found disappointing. I hope it's actually a heat pump.

A while back at one of the Beta showings, I asked the Tesla rep about this. I asked if they recovered heat from the battery/motor cooling system and was told "yes" they do. We didn't get any more technical than that other than for the rep to say Tesla was really trying to squeeze as much eficiency out of the system as possible and they didn't want to throw otherwise usable heat "overboard" when it could be used for cabin heating.

[KBF]

It gets cold in Tucson in the winter time and we occasionally have snow. But I'm planning to travel to the White Mountains where it's properly cold (similar to New England). It's a 200 mile trip with a about a 4500ft elevation gain.

:wink: I suppose it's all relative. While I haven't heard the term 'properly cold' before, IMO that would be if it goes down so low it doesn't matter if you're reading Fahrenheit or Celsius... So cold it doesn't snow much. If you ask some of the Canadian posters here that own Roadsters, the cold has a minor effect on range, and speed is way more important (and wind as well). I recall a Tesla rep saying that extreme heat is worse than extreme cold.

[T@oo]

My understanding is that heat pumps aren't great when the temperatures are very cold (below 0 F).

My heatpump for my house is speced at 2:1 even at -20 degress C. So even at temps that low it's still twice as efficent as using pure electricity. It's a matter of cooling fluid and pressure.

[dspwhite]

Petrol drive cars often take a time to heat up the inside - as long as 20 minutes, and maybe 5 mins for modern cars today.

However, seeing as the Tesla S is electric, is the air instantly warm as soon as you switch it on?

Also, what's the maximum wattage of the internal heating system? For comparison, my convector heater in my house is 2kW, so I hope it's close to that.

[youlikeadajuice]

Does anyone know approximately how much more efficient it is to use the heated seats vs. only the cabin heat in the Model S? I'd rather go with the textile interior, but don't want to take a huge hit on mileage by running the cabin heat, so leather may be necessary. From reading different posts, it's obvious that it's more efficient to use the heated seats, but are we talking a little or a lot? Sorry if this has already been answered, couldn't find the answer I was looking for, thanks!

[steve841]

It's been suggested that heated seat use is preferred to using the HVAC for heating..


Limit the use of resources such as heating and air conditioning. Using
seat heaters to keep warm is more efficient than heating the cabin.

[michiganmodels]

I've had my Model S for three weeks and temperatures in Michigan ranged from 30 Degrees Fahrenheit (Freezing) to 60 Degrees Fahrenheit. From my experience:

1) When temperatures were at or just below freezing, using the HVAC (without seat warmers), the Model S warmed up to 70 Degrees Fahrenheit (cabin temperature) in approximately 2 minutes (or less).
2) Keeping the cabin at 70 Degrees did not significantly reduce range. I drove 70 MPH on the highway with the outside temp at 34 Degrees Fahrenheit and the cabin temperature at 70 Degrees Fahrenheit. I drove 120 miles (all highway). My Watts Per Mile was 315 (270 Miles of range).
3) While warming the cabin has a minimal reduction on range, I noticed that warming the battery does require a lot of juice. In other words, at temperatures of 32 degrees Fahrenheit or below, the first few miles of driving at city speeds (30 MPH to 40 MPH) translated into something like 480 to 520 Watts Per Mile. However, after 2 to 4 miles of driving, the battery did warm up to its optimal temperature and my WPM dropped to something like the low 300s.

I hope this helps.

[youlikeadajuice]

I've had my Model S for three weeks and temperatures in Michigan ranged from 30 Degrees Fahrenheit (Freezing) to 60 Degrees Fahrenheit. From my experience:

1) When temperatures were at or just below freezing, using the HVAC (without seat warmers), the Model S warmed up to 70 Degrees Fahrenheit (cabin temperature) in approximately 2 minutes (or less).
2) Keeping the cabin at 70 Degrees did not significantly reduce range. I drove 70 MPH on the highway with the outside temp at 34 Degrees Fahrenheit and the cabin temperature at 70 Degrees Fahrenheit. I drove 120 miles (all highway). My Watts Per Mile was 315 (270 Miles of range).
3) While warming the cabin has a minimal reduction on range, I noticed that warming the battery does does require a lot of juice. In other words, at temperatures of 32 degrees Fahrenheit or below, the first few miles of driving at city speeds (30 MPH to 40 MPH) translated into something like 480 to 520 Watts Per Mile. However, after 2 to 4 miles of driving, the battery did warm up to its optimal temperature and my WPM dropped to something like the low 300s.

I hope this helps.

Thanks, this info is very helpful and definitely answers my question. I appreciate the help!

[cinergi]

The seat heaters use, for all practical purposes, no power. Cabin heating uses a *TON* of power -- but what I haven't seen anyone talk about yet is what it's like to keep the cabin at 70F when it's 0F outside. The cabin seems to be ridiculously-well insulated. I'm surprised at how little energy is required to keep it at 70 inside when it's 40 outside. You can almost get away with shutting the heat off once the cabin's comfortable inside when it's 45 outside.
It also takes a relatively short burst of energy to get the cabin up to operating temperature if it's been sitting in the cold. Again -- no known observations from 0F. To me, that's the real test. These 40F days just don't count :smile:

I find I'm able to turn the heat down if I have the seat heaters on -- so yes, it helps. I'm just not sure if being able to lower the cabin temp by several degrees will make a significant impact. But I can tell you I'm more comfortable having the seat warmers on and cabin at 73 than I am with them off and cabin at 77 (73/77 is high -- I think my interior sensor has issues or something .. it's not REALLY 73/77 inside).

[widodh]

So we want that iPhone/Android App really quickly so we can turn on the cabin heater while the car is still connected to the grid so we can draw power from there instead of the battery.

Saves you some range again :)

[harry]

I have no idea about the wattage, but the heat is not so quick. Mine blows cold air for a couple of minutes. It would seem that the blower could be held back until the heat was distributed in the system. I'm assuming they are using a scroll compressor as a heat pump, but that's just a guess.

[dspwhite]

Thanks, that's unfortunate. One of the big advantages of an electric car, is that any standard electric appliance can theoretically be used. When I put on my convector fan heater, heat instantly comes out. And so it should be the same with the Model S or any electric car.

I'm guessing that the 'waste' heat is used to supply the interior heating, but this should be at least supplemented by the battery's direct power.

[GSP]

In my Volt the seat heaters use about 50W each, vs about 5000W for the cabin heater. Seat heaters allow me to keep the cabin heater off most of the time, or use a lower setting when it is needed. Seat heaters for all seats should be standard on all EVs.

GSP

PS. The Volt can be set up to turn the seat heaters on when pre-conditioning the cabin (GM calls this "remote start"). I hope Tesla will offer this also.

[Robert.Boston]

I agree it's surprising, but it won't matter much: just use the smartphone app to preheat the car.

[darthy001]

In my Volt the seat heaters use about 50W each, vs about 5000W for the cabin heater. Seat heaters allow me to keep the cabin heater off most of the time, or use a lower setting when it is needed. Seat heaters for all seats should be standard on all EVs.

GSP

PS. The Volt can be set up to turn the seat heaters on when pre-conditioning the cabin (GM calls this "remote start"). I hope Tesla will offer this also.
5000w is it really that much?

Just comparing to an electric heater at home which can heat a livingroom on only 1500w...

Personally i'm not a fan of seatheating so this could be an issue for me. My wife refuses to use it even In the coldest of conditions as well...

[Robert.Boston]

In my Volt the seat heaters use about 50W each, vs about 5000W for the cabin heater. Seat heaters allow me to keep the cabin heater off most of the time, or use a lower setting when it is needed. Seat heaters for all seats should be standard on all EVs.

PS. The Volt can be set up to turn the seat heaters on when pre-conditioning the cabin (GM calls this "remote start"). I hope Tesla will offer this also.
My son really loves heated seats, so it's a shame that the rear seats in the Model S aren't heated. That would be a nice upgrade to have available.

+1 on the idea of activating the seat heat through the smartphone app. The great thing with the MS is that, because there are no buttons, the software has access to nearly everything.

[jerry33]

5000w is it really that much?

That's probably the maximum amount assuming a variable speed scroll compressor heat pump. The difference between your house and the car is that in the house it's maintaining temperature rather than bringing it up from ambient. The Prius' A/C has been measured at over 3 kW (but mostly it runs far lower), so 5 kW is in the ballpark for a maximum on a larger car.

A hair dryer is 1500 W so you can imagine about how long a hair dryer would take to warm up the car.

[GSP]

5000w is it really that much?
..

I think so, but I have not measured it myself. I have seen the 5kW number a few times, but not directly from GM. It is a resistive heater, not a heat pump.

GSP

[cinergi]

The Roadster with its tiny cabin uses over 3kW for heat. And that was insufficient. Increasing the cabin temperature (and air ducts, interior components, etc -- all the cold-soaked stuff) of a car from -10F or worse to 70F requires a serious heating system.

[Brian H]

The Roadster with its tiny cabin uses over 3kW for heat. And that was insufficient. Increasing the cabin temperature (and air ducts, interior components, etc -- all the cold-soaked stuff) of a car from -10F or worse to 70F requires a serious heating system.

Did you see the Roadster hint? Block the passenger vent. Warms the driver side much better, but doesn't much affect the passenger's comfort.

[Doug_G]

The Roadster with its tiny cabin uses over 3kW for heat. And that was insufficient. Increasing the cabin temperature (and air ducts, interior components, etc -- all the cold-soaked stuff) of a car from -10F or worse to 70F requires a serious heating system.

That is true, but the Roadster isn't exactly "sealed" - you get a lot of cold air coming in. If I'm trying to hypermile in winter I turn off the heat, put it on recirculate, set the air flow to the vents, close all the vents (effectively a "no air" setting), and turn on the seat heater. Even so you do get some cold air coming in.

A heat pump should be much more efficient, especially if they can use the battery itself as a thermal reservoir.

[cinergi]

Did you see the Roadster hint? Block the passenger vent. Warms the driver side much better, but doesn't much affect the passenger's comfort.

Yup. I also preheated when I could so the ducts and items in the car would get warm and stop acting like ice blocks. Then the heater only had to overcome poor insulation and air leaks.

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That is true, but the Roadster isn't exactly "sealed" - you get a lot of cold air coming in. If I'm trying to hypermile in winter I turn off the heat, put it on recirculate, set the air flow to the vents, close all the vents (effectively a "no air" setting), and turn on the seat heater. Even so you do get some cold air coming in.

A heat pump should be much more efficient, especially if they can use the battery itself as a thermal reservoir.

Yup like I said above the model s is ridiculously well insulated and has no discernible air leaks so I almost don't need the heat even at 45F. Combined with the heat pump it'll be much more efficient but you have way more cabin space to deal with. The system needs to be powerful enough to quickly overcome cold-soak from sitting in -10F temps. I'll have to crank the heat some time and watch the power meter and estimate the draw. It's quite significant from what I remember.

[mknox]

That is true, but the Roadster isn't exactly "sealed" - you get a lot of cold air coming in. If I'm trying to hypermile in winter I turn off the heat, put it on recirculate, set the air flow to the vents, close all the vents (effectively a "no air" setting), and turn on the seat heater. Even so you do get some cold air coming in.

How did that affect window fogging? I've always found that unless I keep heated air flowing and avoid the re-circ function, I'll get terrible fogging on all windows. Sometimes, even in cool, damp conditions I have to keep the a/c compressor running to avoid window fogging.

[darthy001]

I'll have to crank the heat some time and watch the power meter and estimate the draw. It's quite significant from what I remember.
Such a test would be extremely appreciated. I believe many of my fellow Norwegians would feel the same.

Anything a bit below freezing would do. After having seen your roadster in the snow I believe you sometimes get conitions similar to winter here in Norway;)

[ToddRLockwood]

How did that affect window fogging? I've always found that unless I keep heated air flowing and avoid the re-circ function, I'll get terrible fogging on all windows. Sometimes, even in cool, damp conditions I have to keep the a/c compressor running to avoid window fogging.

Good question. Does the heat pump give one the same anti-fogging benefit as running A/C in an ICE car? I often run the A/C in my Beetle along with the heat to get rid of excess moisture in the spring and fall.

[eledille]

Such a test would be extremely appreciated. I believe many of my fellow Norwegians would feel the same.

Yes, I certainly feel that way!

I think the heat pump may use more power when just started as it pressurizes the system, but I'm not sure. I'm very interested in updates on how the heater performs when it's really cold and how it affects range.

[Doug_G]

How did that affect window fogging? I've always found that unless I keep heated air flowing and avoid the re-circ function, I'll get terrible fogging on all windows. Sometimes, even in cool, damp conditions I have to keep the a/c compressor running to avoid window fogging.

What I've found with the Roadster is that as long as you're driving, there's enough air flow leaking through the system to keep the windshield clear. If you come across a small town and get stopped at a traffic light then it fogs up. So what I do is I leave the heat on but the fan off, so the heat is actually off. When I get to a small town I flip it over to windshield and turn the fan on the lowest setting. That keeps it clear until I get moving again.

None of the above is likely applicable to Model S.

[RDoc]

Good question. Does the heat pump give one the same anti-fogging benefit as running A/C in an ICE car? I often run the A/C in my Beetle along with the heat to get rid of excess moisture in the spring and fall.
That sounds to me like a very good question indeed. AC on with windshield heat for de-fogging works because the AC coil is cold and condenses out the interior air's moisture. The heater then lowers the relative humidity by heating the air so mist on the windshield inside evaporates. Interior heat is free in an ICE vehicle, so that's not a problem.

A heat pump produces heat on the interior of the car and cold outside, or in the cooling system, so there's no dehumidifying function beyond the temperature difference the heater produces. I wonder if the Tesla has a windshield heating system that uses the AC to chill the air, then resistance heaters to warm it up or possibly an interior to interior circuit in the heat pump.

Anyone with an S have any experience with the de-fogging function of the heating system or know how it works?

[Jason S]

I've had my Model S for three weeks and temperatures in Michigan ranged from 30 Degrees Fahrenheit (Freezing) to 60 Degrees Fahrenheit. From my experience:

1) When temperatures were at or just below freezing, using the HVAC (without seat warmers), the Model S warmed up to 70 Degrees Fahrenheit (cabin temperature) in approximately 2 minutes (or less).
2) Keeping the cabin at 70 Degrees did not significantly reduce range. I drove 70 MPH on the highway with the outside temp at 34 Degrees Fahrenheit and the cabin temperature at 70 Degrees Fahrenheit. I drove 120 miles (all highway). My Watts Per Mile was 315 (270 Miles of range).
3) While warming the cabin has a minimal reduction on range, I noticed that warming the battery does require a lot of juice. In other words, at temperatures of 32 degrees Fahrenheit or below, the first few miles of driving at city speeds (30 MPH to 40 MPH) translated into something like 480 to 520 Watts Per Mile. However, after 2 to 4 miles of driving, the battery did warm up to its optimal temperature and my WPM dropped to something like the low 300s.

I hope this helps.


Thanks, this info is very helpful and definitely answers my question. I appreciate the help!For reference, this afternoon/evening (some with lights on) I was driving 70 for about 150miles at saw about 300Wh/mile but didn't need to use heating or cooling at all. Did use the lights for about an hour. For the entire 200 mile trip the average was 304Wh/mile with mostly freeway driving.

Therefore I'd say the heating and lights are maybe a 5% difference (15/300).

[cinergi]

I've used the defroster a few times to defog. I didn't pay attention to what it was doing (AC + Heat? Would be hard to tell) but it was effective.

[eledille]

I really wish Tesla would add a tab to the display which would show stats like instantaneous voltage, amps, temperatures (battery inlet, battery outlet, motor, inverter, ...) etc. That would make so many questions so much easier to answer, and they have those numbers in there somewhere already.

With this info, we would know exactly how much power the heater consumes, why the car just went into reduced power mode, and any number of other interesting questions.

[William13]

When I start the car in the cold it draws a lot of power for a few minutes, warms up quickly, then the power usage goes down. It stays higher than usual for another few miles then drops to something similar to it warmer weather standard.

Maybe someone with more patience than I have will try to answer this question.

[cinergi]

Heat & A/C fully-cranked (was in my garage so not bitter-cold but should consume approximately the same power as I manually set everything to max):

11955

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I've used the defroster a few times to defog. I didn't pay attention to what it was doing (AC + Heat? Would be hard to tell) but it was effective.

This does run the AC. Separate systems.

- - - Updated - - -

Counting pixels (haha) it's about 16 out of 43 to 20 kW or about 7.5 kW for full blast.

[Doug_G]

Counting pixels (haha) it's about 16 out of 43 to 20 kW or about 7.5 kW for full blast.

Interesting - about the same as the Roadster at max heating.

[tezco]

My Leaf heats a water bath instead of the air directly. This means that the blower circulates cold air for about 10 minutes until the water heats up. So, I normally call the car up on the App and turn on the heat about 10 minutes before I plan to leave. The Leaf uses up to about 4,000 watts for heating initially when in regular drive mode. Once the cabin warms up the power needed drops unless it is really cold outside. If you switch to Economy mode (gives you better regen), the heater input is cut back to 1,500 watts, which isn't sufficient below about 20 degrees. Tesla system works better.

[cinergi]

So I just drove around for 100 miles for the fun of it this evening ... it was about 60F in my garage, 35F in Boston, and 26F during the coldest parts of my trip (usually 30F or under). I was attempting to observe whether the 19" winters had better range properties than the 21" summers. I can't tell -- too hilly around here. But since I was doing that, I had the heat off. The insulation in the car is pretty impressive.
First, I actually had to go full manual and set the temp to LO (no heat), fan on 1, and blow air on windshield -- because otherwise I'd fog up!
So I've got air blowing into the cabin ... yet after 45 miles of driving, the cabin was 57F. I had the heated seat on, wearing a t-shirt and the tesla sweater (I don't think it was zipped up, either). I was pretty comfy the first 25 miles ... and then I could tell I should have the heat on -- but it wasn't bad. After 45 minutes (where it was 26F out and cabin was 56-57) I turned the heat to 70. It got into the mid-to-upper 60's in the cabin pretty quick. WHPM took a pretty good hit for the first several miles. After that, I was doing between 375 and maybe 410 WHPM while driving 72 MPH with the heat at 70 (that's with hilly terrain -- very difficult to observe impact of turning the heat on). Once the cabin got up to temp, the fan was running at 2-3 ... couldn't hear a thing... very comfortable inside.

Yesterday my car was sitting outside in 35F temps for several hours, but the inside of the car never got that cold (???) so heating it up and whatnot was quick. Will be really really interesting to see a cold-soaked car in 0F weather!

[strider]

Does it automatically turn on the A/C when put into defrost mode?

[cinergi]

Does it automatically turn on the A/C when put into defrost mode?

If you hit the defrost button, yes. In this case, I just manually selected to direct air to the windshield.

[sreehyd]

So I just drove around for 100 miles for the fun of it this evening ... it was about 60F in my garage, 35F in Boston, and 26F during the coldest parts of my trip (usually 30F or under). I was attempting to observe whether the 19" winters had better range properties than the 21" summers. I can't tell -- too hilly around here. But since I was doing that, I had the heat off. The insulation in the car is pretty impressive.
First, I actually had to go full manual and set the temp to LO (no heat), fan on 1, and blow air on windshield -- because otherwise I'd fog up!
So I've got air blowing into the cabin ... yet after 45 miles of driving, the cabin was 57F. I had the heated seat on, wearing a t-shirt and the tesla sweater (I don't think it was zipped up, either). I was pretty comfy the first 25 miles ... and then I could tell I should have the heat on -- but it wasn't bad. After 45 minutes (where it was 26F out and cabin was 56-57) I turned the heat to 70. It got into the mid-to-upper 60's in the cabin pretty quick. WHPM took a pretty good hit for the first several miles. After that, I was doing between 375 and maybe 410 WHPM while driving 72 MPH with the heat at 70 (that's with hilly terrain -- very difficult to observe impact of turning the heat on). Once the cabin got up to temp, the fan was running at 2-3 ... couldn't hear a thing... very comfortable inside.

Yesterday my car was sitting outside in 35F temps for several hours, but the inside of the car never got that cold (???) so heating it up and whatnot was quick. Will be really really interesting to see a cold-soaked car in 0F weather!


Thanks Cinergi for all your tests and observations . It is impressive to note that MS is very well insulated and holds inside temperature. So just to get a fair understanding, How was energy consumption with & without Heat/AC on in same drive and speed etc ? If you have already tested .

[Kipernicus]

Counting pixels (haha) it's about 16 out of 43 to 20 kW or about 7.5 kW for full blast.


So I just drove around for 100 miles for the fun of it this evening ...

You are da man! Always going above and beyond the call of duty. Thanks

[cinergi]

Thanks! It's easy -- this stuff, including driving the car, is a lot of fun! So it's not "work" to me :smile:

With respect to HVAC on vs. off, it's very difficult for me to get an accurate number given the hilly terrain plus the fact that I've changed my tires recently. I will do five circular trips (30 miles each): two with heat on, two with it off, and the first one to "warm up" the car and remove any "first drive results in different numbers" stuff at some point.

[ddenboer]

One thing I've noticed in my car is that I almost always have to have air blowing on the windshield to keep from fogging (we've had a lot of rain here lately). When I do this, no matter what temp I have the car set to, it never reaches it, and I can actually feel the cold air blowing on me instead of the warm.
Also, no matter what temp I set to, or what ventilation option, I have never felt air blow into the back seats, and my kids complain about being a little cold in the morning rides to school.

[Jeeps17]

... snip ... no matter what temp I set to, or what ventilation option, I have never felt air blow into the back seats, and my kids complain about being a little cold in the morning rides to school.

That could be an issue, especially for those using rear facing seats, if the second row passengers are feeling chilled.

Is there ANY ventilation back in the trunk? The kids sitting there in winter will have the hatch window radiating cold right above them...

[jerry33]

That could be an issue, especially for those using rear facing seats, if the second row passengers are feeling chilled.

Is there ANY ventilation back in the trunk? The kids sitting there in winter will have the hatch window radiating cold right above them...

Perhaps one of these 12V heaters would work. (http://www.amazon.com/Direct-Hook-Up-Ceramic-Heater-Cooling/dp/B004EKHZ5U/ref=sr_1_12?ie=UTF8&qid=1354461566&sr=8-12&keywords=12v+car+heater) None have particularly good ratings, but you're not trying to replace the heating system, just add some additional heat where there isn't any now.

[Robert.Boston]

Suggestion: have a "vent" mode for the HVAC, that simply pulls in fresh air, or recirculates internal air, without heating or cooling. This mode would conserve energy while providing some air flow. Yes, cracking a window would have a similar effect, but that's noisier and less aerodynamic.

[Al Sherman]

Suggestion: have a "vent" mode for the HVAC, that simply pulls in fresh air, or recirculates internal air, without heating or cooling. This mode would conserve energy while providing some air flow. Yes, cracking a window would have a similar effect, but that's noisier and less aerodynamic.

<<<+1>>>

[tdelta1000]

Suggestion: have a "vent" mode for the HVAC, that simply pulls in fresh air, or recirculates internal air, without heating or cooling. This mode would conserve energy while providing some air flow. Yes, cracking a window would have a similar effect, but that's noisier and less aerodynamic.



I agree...it make a lot of sense.

[William3]

Wait, what?
There's no vent mode?

[cinergi]

Wait, what?
There's no vent mode?

No button for it, no. You have to manually turn up the fan, turn off the A/C, and set the temp to LO.

[jerry33]

Suggestion: have a "vent" mode for the HVAC, that simply pulls in fresh air, or recirculates internal air, without heating or cooling. This mode would conserve energy while providing some air flow. Yes, cracking a window would have a similar effect, but that's noisier and less aerodynamic.

I never understood why cars don't do this. There are many days where it's cool outside but the car heats up because of the glass. If you don't want the windows open, then you have to run the a/c even though the air temperature outside is just right to keep the interior cool.

[mknox]

I never understood why cars don't do this. There are many days where it's cool outside but the car heats up because of the glass. If you don't want the windows open, then you have to run the a/c even though the air temperature outside is just right to keep the interior cool.

In my current car, and pretty much every car I've owned, when the system is in "Auto", I can just tap the A/C button to turn it off and it continues to work in automatic mode sans the a/c compressor. Wouldn't Model S work the same way?

[jerry33]

In my current car, and pretty much every car I've owned, when the system is in "Auto", I can just tap the A/C button to turn it off and it continues to work in automatic mode sans the a/c compressor. Wouldn't Model S work the same way?

In some cars you have to dig down through a menu to do this. Auto should be smart enough to use cool outside air when possible.

[Vger]

Has anyone verified if you can run the heat in the Model S while plugged in and charging? This is a key capability lacking on the Roadster. The Roadster only lets you use the seat heaters while charging. If you are sitting in the car while charging at a road trip stop, it would be nice to be able to stay toasty, even if it slowed your charge somewhat.

In my Roadster in sub-freezing temperatures, I resorted to a sleeping bag to keep the heat from the seat heater around my body. That works in a pinch. Good for Canadians and Norwegian to know. :wink:

[Robert.Boston]

Yes, I just went out and checked. HVAC and heated seats stay on while charging.

[strider]

In my current car, and pretty much every car I've owned, when the system is in "Auto", I can just tap the A/C button to turn it off and it continues to work in automatic mode sans the a/c compressor. Wouldn't Model S work the same way?
It does. A/C on/off is right on the primary (always visible) HVAC control. You can also slave the right scroll wheel to the fan speed. It only gets complicated if you want to adjust where the air goes. That is one level deep.