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

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5
votes
2answers
887 views

When insulating with closed-cell Spray Foam, what ERV and HVAC resizing considerations should I bear in mind?

I am building a 2800 sqft, two-story brick home in Austin, TX. I have heard many good things about the benefits of insulating with closed-cell Spray Polyurethane Foam (ccSPF)1, and have requested ...
2
votes
0answers
162 views

Is mold growing in my ductwork? [closed]

I am currently in a battle with my landlord over what I believe to be mold growing on the fiberglass liner of the ductwork in my apartment. He is having a specialist come to test it tomorrow, and I ...
0
votes
2answers
8k views

Is it normal for the A/C to be dripping from top pvc that's coming from attic?

I thought I remember being told that water should drip (condensation) from the bottom pvc that comes out of the house but it should never drip from the top pvc. I thought he told me that if it ...
4
votes
1answer
2k views

Adding AC to forced air system

We have an old house that happens to have forced air. Unfortunately, according to an HVAC tech it looks like there aren't sufficient return vents to add a compressor to our furnace. I guess I'm ...
11
votes
5answers
11k views

How can I calculate how large an airconditioner my house needs?

I know there are a lot of possible factors that go into determining the size of the air-conditioning system a house needs. Is there a standard way of calculating what is needed, or do A/C companies ...
7
votes
1answer
1k views

AC issues / Insulation of vaulted ceiling

Issue: If it's hot outside, ~90F, house temperature can't get below 79F. Background: 6 year old house, vaulted ceiling with 1 ceiling fan in family room where thermostat is (also 3 large windows, ...
2
votes
1answer
5k views

Why is there water dripping from my ceiling AC vents?

I have a one story house with hot water heat. The house also has forced air AC ducts running from the attached garage, in the attic, down into the living room, bedrooms, and kitchen. At certain times ...
1
vote
1answer
809 views

Installing a duct fan

For a room in the basement we connected a ceiling register to an existing duct. It is not very strong, but I found this product that might make it a little more powerful: Does anybody know how ...
2
votes
1answer
129 views

A/C Emergency Cut-off Cleaning and Maintenance

I found my thermostat not working. After googling for a solution, I found that I may need to check my emergency cut-off. I know of a pipe that if tripped will turn-off the A/C, so I took the pipe ...
2
votes
1answer
4k views

Air deflectors on floor registers and cooling efficiency

I was once told by an HVAC technician to avoid using air deflectors on floor registers during the summer. The reason was that the last thing you want to do is to direct the heavier, colder air ...
3
votes
1answer
214 views

Improve AC flow to secondary ducts

I have an AC which has 3 ducts coming out of it. Only one duct gets flow - I'm guessing the AC fan blows right into it. What can I do to improve the flow?
5
votes
2answers
6k views

HVAC vents - does wall or ceiling mount matter?

I'm going to add some crown moulding to some bedrooms. I've got HVAC vents mounted near the top of the wall and the moulding will cover part of the vent. I want to move the vents out of the way. I ...
2
votes
1answer
133 views

Help me choose AC model

I need air conditioning (no heat; I've got hot water radiators) for the main floor of my house (around 1000 ft2). I was offered the following models (mostly Carrier) (ordered by price, descending): ...
1
vote
1answer
565 views

Furnace Airflow

I have central air. When the furnace comes on, we can feel air coming out of the registers for a few minutes, then the airflow stops. If we turn it off for a few hours, we can turn it on again and get ...
4
votes
2answers
116 views

DIYer to skilled tradesperson

What is the process a DIYer has to go through to become a skilled tradesperson? Are the only options apprenticeships, or are there other paths to follow to learn a trade/become licensed? What type ...
2
votes
0answers
597 views

What are good Relative Humidity and Temperature settings on an MHRV and are the settings related?

I need to configure the threshold Relative Humidity and Temperature settings on an whole house MHRV system. The way the system works is that if the RH threshold is exceeded the system increases the ...
1
vote
2answers
6k views

How do I connect a dryer to a dryer vent?

I just moved my dryer (gas) a couple feet to a better location in the basement. It is actually now closer to the existing dryer vent to the outside of the house. The previous owner has it connected ...
2
votes
1answer
2k views

How do I fix a condensate drain line that froze in my split electric system with heat pump?

I have a split electric system with a heat pump. It looks like my condensate drain line is frozen. I switched to supplemental heat which does not use the heat pump. Is this enough for now? Our ...
2
votes
2answers
4k views

How can I tell what kind of heating system I have?

Seems like a simple question, but I've had a very hard time finding a definitive answer to this. I went to the hardware store to buy a replacement for a faulty thermostat and when I arrived and ...
4
votes
3answers
125 views

Geothermal Resources

I am very interested in learning more about Geothermal solutions for my house. What are the best resources for learning about and planning a Geothermal systems for a residential house? Also, does ...
5
votes
2answers
8k views

Is it OK to have heating registers and returns near the ceiling?

I've got a question about a new house - a friend of my mother's is buying a new place and when she did a walkthrough (before the drywall was up), she noticed that all the heating registers and returns ...
2
votes
1answer
263 views

HVAC electric thermostat panel “goes dead” and then live again all the time

I have this digital thermostat controlling my heater (gas). When I turn it on to lets say 66 deg, and the house is at 60, the HVAC will start working of course. Problem: After few minutes, the ...
7
votes
2answers
1k views

Is there any legitimate reason to have a direct vent between utility room and attic?

I've been doing some sealing and insulating in my attic, and discovered a purpose built vent directly from the utility room into the attic space. See most of these photos The house is in a ...
3
votes
3answers
21k views

Why is my furnace blowing cold air?

My HEIL 7000 natural gas furnace has stopped working what are the most likely causes, and how to verify faulty parts? Normal operation routine Thermostat sends "need heat" signal. Exhaust blower ...
4
votes
1answer
1k views

What's wrong with my thermostat (fan / limit control)?

I previously asked about wiring the White-Rodgers fan/limit control on my wood stove. It's now wired and the wood stove is fired up. I ran the fan wires to the fan (hot) and I capped the limit ...
5
votes
2answers
6k views

How do I install a wood stove as an auxiliary heat source?

I have a house with a forced air electric furnace. We've also got a wood-burning stove adjacent to the furnace. I didn't have it installed, and I want to understand if it's been done properly, and ...
2
votes
2answers
2k views

How do I clean an AC condensate pan?

I have a Ducane HVAC system that started leaking out of the evaporator coil housing. Mine looks like the EU1P. I read that i need to clean out the drip pan. II tried cleaning it by sucking out the ...
2
votes
2answers
1k views

How do I repair loose ductwork?

The ductwork in our 30 year old house has started coming loose where it comes up through the floor. It's nailed to the subfloor, but in several places, the nails have come loose, leaving gaps of an ...
1
vote
1answer
150 views

Fan between rooms?

I presently work at home, which means that I spend a lot of time in my office (ya think?). Unfortunately, this room is not a good one for air conditioning (or heating) in the house. I can often get 8 ...
1
vote
2answers
191 views

How do I choose a furnace airfilter?

I have a furnace/air-conditioner that can support filters of various thicknesses: 1", 2", or 4". Filters are available in various MERV ratings. How should I decide which filter to use?
4
votes
3answers
2k views

Is an interior laundry room without an HVAC vent a code violation?

Currently looking at a home which has a nice 2nd floor laundry. Vented dryer, nice rack for hanging clothes, etc. However, it's in the center of the home and does not contain an HVAC (central air) ...
3
votes
2answers
4k views

How do I install a jump duct?

Our master bedroom is considerably warmer than the living/dining/kitchen area of our house, and we've been setting the thermostat quite lower than we'd like in order for the bedroom to get cool enough ...
1
vote
1answer
98 views

Weather stripping a door in an outside bldg

I have an office in the garage that is a standard room with insulation and an AC unit (8500 BTU AC in a 9' 3" tall room, 5" 4' wide). The room gets rather hot and I found the issue to be with the door ...
4
votes
1answer
1k views

two condensate drains?

we just had a new AC system installed in my florida house. the unit is in the garage, and the air handler is vertical with the evaporator on top. the unit he removed had 2 condensate lines: one that ...