Home Improvement Stack Exchange
Home Improvement Stack Exchange

Questions tagged [furnace]

The furnace is part of an HVAC or central heating system used to generate heat. Typically this is done with gas, a heat pump, or an electric element. For hot water and radiator based heating, use the boiler tag.

For more general questions, see , , and

Related components include:

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Do thermostat-controlled, auto-adjust HVAC vents exist?

The residential forced-air HVAC systems I have seen are controlled by a single thermostat in one room. One has to manually adjust the vents in order to adjust the temperature in other rooms. Is there such a think as thermostat-controlled,…
Vebjorn Ljosa
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How do I identify the C terminal on my HVAC?

How do I identify the C terminal on an HVAC, furnace, or boiler? If the terminals don't have a screw labeled C what should I look for on the wiring diagram? What steps should I take if a wiring diagram cannot be found or if it indicates that a C…
BMitch
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What does a Summer/Winter switch on furnace air ducts do?

On some of our furnace ducts, there is a switch/valve for Summer/Winter or S/W. What does changing this switch/lever accomplish? Can bad things happen if I forget to switch it? Bonus question: Pictured below, an Aprilaire humidifier control unit…
The Other Steven
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Does lowering the blower speed of a forced-air furnace lower its efficiency?

My gas furnace has two options for the blower speed: MED, and MED-HI. It had been set on the higher speed, but that was too harsh, so I lowered it to the slower speed. Does that have any impact on the efficiency of the unit?
Dave
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How many wires can be connected to the C terminal at the furnace?

I'd like install a new Wi-Fi thermostat. The old one didn't have a C-wire but luckily there is an unused wire on both sides (one coming out of the wall and one at the furnace not connected yet), so I am going to use this unused wire as the C-wire.…
user46790
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How can I audit my furnace?

I want to keep track of when my furnace is on, with an eye to reducing how much energy I use to heat my house. I could compare it with weather data (temperature, wind speed, precipitation). I could see what it saves to turn the heat down when we're…
Jay Bazuzi
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Should I insulate steam pipes in the basement?

I have a steam-radiator heating system. The furnace is in the (unfinished) basement, and the steam-carrying steel pipes spread out across the basement ceiling before going up into the rest of the house. Should I insulate these pipes in order to…
Vebjorn Ljosa
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Is it possible to upgrade A/C to a heat pump by only replacing outside unit?

I have a standard southern California tract home that was built in 2010. It has a Carrier gas-fired furnace, Carrier 5-ton A/C, and a smart thermostat. I'm slowly upgrading the major systems and replacing gas with electric wherever…
Chris O
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How much energy will continuously running a furnace fan use?

We have a bi-level (tri-level? There's a small entry way and utility room, then an upstairs living area and master bedroom and a downstairs living area with bedrooms) in mid-Michigan. The downstairs is naturally quite cooler than the upstairs, but…
Peter Tirrell
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What does this device on my new furnace do?

Can someone please tell me what this is? I had a 35-year old oil furnace replaced recently and the new furnace is obviously more complex and has many safety features the old one didn't. I've looked it over and understand what all the new devices…
Carey Gregory
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Should I relocate the HVAC unit in my attic?

I have had a couple of estimates to replace our HVAC system and one contractor says he would relocate the system to a more central location in the attic. One says there is no need to relocate. There is an additional cost to this relocation, of…
Cathy
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How to electrically ground a gas furnace connected with an armoured cable

My gas furnace will not turn on. I verified 120V where the armoured cable enters the furance, so I was going to continue testing for voltage before and after the transformer (with the door safety switch pressed in and 24V call-for-heat manually…
Julius Seizure
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Where should my furnace filter go in a Lennox G40UHX series furnace?

I have a Lennox G40UH(X) series furnace, which is installed in our attic (We have a single-story house on a slab). Because the furnace is installed in the attic, it is "laying down" on its side, and the incoming air is piped into what would be the…
Jared Harley
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Why are furnace/central AC blowers so inefficient?

I can buy a ceiling fan from Home Depot capable of moving 5,000 CFM of air for about $50, and it uses a mere 50-60 watts while doing it. By contrast, most furnaces seem to have blowers that operate in a much lower CFM range but use humongous 1/2 or…
iLikeDirt
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How to Lower the Ouptut of Oversized Furnace

Questions I would like to lower the output capacity of my furnace if possible. How can I do this? Is it worth doing, or should I just live with it? Is there an easy way? Some ideas: replace burner nozzles with smaller nozzles, replace burner with…
zerpsed
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