Questions tagged [hvac]

(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

3646 questions
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How can I add a "C" wire to my thermostat?

So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat location?
Aaron
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Can I heat one room and cool another with an in-wall AC?

I work in a bakery. It gets warm in the summer, but not warm enough for bread to rise without extra heat. We have a 'proofer room' where the bread sits while the dough rises. The room is heated by two baseboard heaters, and another space heater.…
38
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9 answers

Can I gain AC efficiency by spraying condensate water on the outdoor coils?

Recently, I was working from the basement and I noticed tonnes of condensate water going down the drain, and thought I might re-use it to improve the efficiency of my home AC system. So I put a condensate pump (tank&float combo unit) in the drain…
28
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6 answers

What are the pros and cons of a whole house humidifier?

In the winter, my house (~2500 sqft) becomes unbearably dry. Last winter, my wife and I used a tiny humidifier for the master bedroom to keep us from completely drying out, but since then I have been exploring a whole-house solution, complete with…
Nate
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28
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9 answers

Why does my house heat up, even when it's cool outside?

Summary The question pretty much says it all. It's probably a ridiculously easy one to answer. It's cool outside but I know that my house is heating up because my AC kicks on periodically. I've had this experience in multiple houses, so I presume…
conman
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28
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6 answers

How to improve HVAC system to make upstairs rooms more comfortable?

My home was built in 1985 in the US with conventional HVAC design of that time. Wooden frame house. It has central air conditioning (ducted) and we upgraded to a natural gas furnace recently. We experience both hot and cold temperature extremes in…
allquixotic
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27
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9 answers

Should my neighbor run their AC refrigerant lines through my garage?

I live in a 2-unit town home. I have installed an AC on the side of my unit. My neighbor would like to install an AC for their unit. However the city codes will not allow them to install it on the side of their house since it is too close to the…
V Maharajh
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27
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2 answers

What is an air conditioner compressor hard start kit and how does it work?

My air conditioner compressor wasn't functioning properly recently. The compressor wouldn't start when the start relay energized. A HVAC technician diagnosed the problem nebulously as "It needs a hard start kit because the compressor is getting old…
ndemarco
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26
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1 answer

Humidity Levels

What is a healthy and safe humidity level that I should try to keep my house at?
Sam Erde
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26
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5 answers

How can I protect a frozen heat pump in cold weather while waiting for service?

Yesterday I noticed that my Carrier heat pump was struggling to keep up with my thermostat settings inside the house. It was around 35°F (2°C) outside, I had the thermostat set at 72°F (22°C), but the internal temperature wasn't rising above 70°F. I…
user3103523
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1 answer

How do you trigger the HVAC with wiring only?

I have a HVAC that has the usually wiring C R G W Y Pinouts What wires do I need to connect to turn on Heating? What wires do I need to connect to turn on the A/C? Is there a risk of damaging any circuitry in doing this? Is there a way of finding…
Ashitakalax
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25
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3 answers

Is running ethernet cable through an air return allowed under US code?

I'm looking to wire up the second floor of my house and the cold air return provides a convenient, straight run from the office to the utility room. Is it safe and within code to run ethernet cable in the air return? The air returns are not metal…
Freiheit
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13 answers

Do smart or programmable thermostats actually save money?

I am looking at replacing all the thermostats in my house. I have hot water baseboard heat and forced air A/C. Each room's baseboard heat is controlled by a thermostat in that room. I tend to prefer simple mechanical interfaces to digital "smart"…
JoshuaD
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24
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7 answers

Ethernet cable instead of Thermostat wire?

I need to pull new wire from my furnace to my thermostat and was wondering if there would be any problems in using an Ethernet cable instead of standard thermostat wiring. The reason being is I have left over cat6 cable and figured the wire should…
Metro Smurf
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4 answers

What's the most common cause of A/C refrigerant lines freezing?

I noticed my house wasn't getting under 75°F this weekend when I had the thermostat set for 70°F. Since I'd done a lot of drywall sanding inside recently, my first idea was to replace the filthy air filter. My first indication that the air filter…
Doresoom
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