2 posts, read 12,346 times Originally Posted by Bulldawgfan I think you have received the answer to your question ... but I would like to suggest one thing. If you place your Thermostat fan switch to the "on" position you will be filtering your air all the time. The fan draws very little power (compared to the compressor outside). As you need heating and cooling the system will still do what it needs to and you will be moving the air in your home constantly through the filter. Now this means that your filter will get dirty sooner... but I fail to see how this is a bad thing... collecting up the dust and dirt in your home. Interesting idea on the fan running all the time for air filtering reasons. Anyone else do this? 1 posts, read 3,553 times 407 posts, read 200,299 times 5,652 posts, read 4,227,188 timesIt has been very cold 5 to 10 degrees and now in the 40s. The Carrier air condition condenser turned on this morning and will not sut off. While the furnace is still keeping the house at 70 degrees.

No cold air is coming through the heat ducs. No it is not a heat pump. Thermostate seems to be working fine. When we purchased this home, that happened when heating turned on. Found they had wired the heating and cooling for a heat pump system at the Thermostat. Wired it back for heating and cooling systems, and it worked perfectly. Immediately cut the electric and gas bills in half over previous year. So it finally got cold here in AZ. We switched our thermostat from A/C to Heat. Now for some reason when the electric heater runs, the A/C condenser unit outside kicks on too. This is our first winter here in the house. The vents do blow warm air, not hot, but warm. Where do I start looking? Is it possible it is just a thermostat issue? or could it be a bigger problem? Are you sure the AC isn't actually a heat pump? A heat pump looks about the same as an AC, but in winter it runs in reverse to pump heat into, instead of out of, the house. Examine the markings on the outdoor unit and see if it's a heat pump.

If so, this is normal. Turns out it is a heat pump / AC unit.Browse other questions tagged air-conditioning thermostat heater or ask your own question. So i had this experience when driving in a cold night, where my windshield just got all blurry. I knew that on the drivers manual they say you should turn the hot air and soon it will go off, but my friend that was on the passenger seat said the cold air will work too. We turned the AC off and re-experienced the fact. I got the chronometer and and got the time of both situations, defog with hot and cold air and there were really small diference btween them. How can i explain this in terms of thermodynamics? The reason the cooled air appears to work about as well as the heated air is that the cooled air is also de-humidified. For the fastest de-misting, you want warm and dry air. Car owner manuals often tell you to turn on the air conditioner and the defroster at the same time in these conditions. The air conditioner cools the air, which forces it to dump much of whatever moisture it contained.

The heater then warms the air again, but without adding any moisture back. automotive ac repair tipsThe result has high capacity for obsorbing more moisture, so quickly removes the condensation from the inside of the windshield.home central ac reviews My experience over many years has been similar, except I find, the cold air from the air conditioner directed to the windscreen demisted the windscreen faster than hot air similarly directed.ac unit price list Currently it is winter were I am. On cold humid nights when the car heater is turned on, the inside of the windows mist/fog up. By turning on the air conditioner while the heater is on allows for the car interior to be warm and for the windows to be mist/fog free, particularly if air directed to the windscreen.

While living in a tropical climate I had a similar experience, but in reverse; warm humid air, turn on the air conditioner and the outside of the windscreen misted/fogged up. That was easily fixed by clearing it with the wiper blades. This is all due to the dew point of the air and water vapour mixture in contact with the car windows. “The dew point is the temperature at which water vapour condenses into liquid at the same rate at which it evaporates”. Sufficiently change the temperature of the air in contact with the windows by either heating it or cooling it and the dew point changes. Water vapour, from the air no long condenses on the windows and the windows do not mist/fog up and what mist/fog condensed out onto the windows evaporates back into the air. This happens on car windows because they are the only part of the car which are in contact with the interior air of the car and the exterior atmospheric air. They are the barriers between the two. Car roofs have lining which acts as insulation and another barrier.

Car doors and pillars have air gaps in them which acts as another form of weak insulation. As to which is the better way to demist car windows,it depends on your circumstances at the time and whether you want to be cold or warm at the same time.Browse other questions tagged thermodynamics or ask your own question.With the warmer weather finally arriving, many households are switching their thermostats from heating to cooling. Here’s how to do it on the Nest Thermostat. The Nest Thermostat allows you to control and manage the device remotely from your smartphone, and it even comes with learning capabilities that can learn your habits and patterns and eventually automatically adjust the thermostat for you. However, sometimes it can be the littlest of features that are hard to find. Case in point: how do you switch the Nest Thermostat from heating to cooling, or from cooling to heating at the turn of the season? It’s actually really simple and you can do it from either the Nest app or on the Nest Thermostat unit itself.

Open up the Nest app on your phone and select your Nest Thermostat from the main screen.It may also say “Cool” depending on what you already have it set at. A pop-up will appear, giving you several options. If you want to switch to your air conditioning, tap on “Cool”.  If you want to switch to heating, tap on “Heat”. You can also turn off your Nest Thermostat from here, and there’s even a setting where you can choose both Heat and Cool at the same time. (We’ll discuss that more in a minute.) When you switch from Heat to Cool, the thermostat’s set temperature will automatically jump to a higher setting, and from there you can adjust it as needed. It will do the opposite when you switch from Cool to Heat, going down to the last temperature you had it set at before you switched it to Cool. When you switch to “Heat-Cool”, the Nest Thermostat will automatically turn on the furnace or the air conditioner whenever either is needed, rather than only having one or the other enabled at any one time.

Using this setting, you can set a temperature range that you want to keep your house between, and the Nest Thermostat will take care of it all automatically without needing to manually switch back and forth between Heat and Cool. Switching from Heat to Cool and vice versa uses the same method in the app, but obviously it’s a bit different on the smaller screen of the Nest Thermostat. Press on your Nest Thermostat unit to bring up the main menu. Use the silver scroll wheel and go to “Thermostat”. Push on the unit to select it. From there, scroll and select either “Heat”, “Cool”, “Heat-Cool”, or “Off”, just like you would in the Nest app. The “Heat-Cool” setting can be great for when the seasons are just changing, meaning that it’s getting warmer outside, but there are still days where it can get cold (and vice versa in the fall). Because of this, the Heat-Cool setting keeps you from having to constantly switch back and forth between heating and cooling when the weather is kind of unpredictable.