44 votes
Accepted

Are mobile air conditioning systems an inherently flawed design?

As has already been mentioned, “dual hose” “portable” AC units do exist. So, we need to consider two separate questions: are single-hose ACs bad, and are portable ACs bad? Single hose operation For ...
Kevin Reid's user avatar
  • 4,044
38 votes

Can I heat one room and cool another with an in-wall AC?

I'm not an expert to tell you whether this is actually a good idea, but an AC unit used for heating is called a heat pump. There are two differences between "a heat pump" and "an air conditioner": ...
Kevin Reid's user avatar
  • 4,044
35 votes
Accepted

Does A/C encourage mold growth

Yeah, that advice was super wrong. Moisture encourages mold growth. After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then ...
Harper - Reinstate Monica's user avatar
35 votes
Accepted

Do I really need an air conditioner filter?

Yes, you'll distribute crud through your ventilation. On top of that, you'll accumulate crud in your AC unit. BAAAAADDD idea.
Darthg8r's user avatar
  • 566
31 votes
Accepted

How to disconnect air conditioner lines from outdoor unit?

Absolutely not. These lines contain a refrigerant/lubricant mix under pressure. The lines also must have no dirt, water or air in them, i.e. they have to be bled, evacuated to fairly high vacuum and ...
DrMoishe Pippik's user avatar
29 votes

What type of cable should I run to future-proof an outlet for an air conditioner?

If you truly want to future proof, install conduit instead of cable. This will allow you to pull whatever wire you need, once you've decided what you want. 3/4" conduit should work fine, and would ...
Tester101's user avatar
  • 131k
29 votes

Can I heat one room and cool another with an in-wall AC?

Yes, this would work, but I caution you to consider that the hot side of the A/C could produce airborne water droplets full of bacteria. The typical through-window or through-wall air conditioner ...
MTA's user avatar
  • 11.2k
26 votes
Accepted

If an AC guy checks a system and finds it 100% out of refrigerant, what is the correct next step?

If the system still had pressure you could add the correct amount of refrigerant and get the system running again. However the correct fix should be to find the leak, fix the leak, add suction and ...
d.george's user avatar
  • 12.4k
26 votes
Accepted

Replaced Blower Motor, but A/C won't stay on unless power button is held down

I don’t think that is a power switch. That is a safety switch that is depressed by the cabinet panels when you put everything back together. It should not work unless it is depressed. You should be ...
Rward73's user avatar
  • 234
25 votes
Accepted

How to get rid of CO₂ in a house with A/C in hot summer?

You want an high-efficiency heat exchanger. https://en.wikipedia.org/wiki/Heat_recovery_ventilation Basically, you pipe in fresh air, but have it cooled before, while you heat out the air that is ...
Jeffrey's user avatar
  • 2,031
25 votes

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

Clamp Power Meter Buy or borrow a clamp power-meter with a "kWh" feature, that is, the ability to perform an energy measurement. Not all clamp meters have this, e.g. a "True RMS" ...
P2000's user avatar
  • 15.8k
21 votes

Condensor went, HVAC guy is blaming electrician, is this possible?

Per the National Electric Code (assuming you are in the US), #8 is for up to 40A, the Minimum Circuit Ampacity (MCA) was 32A, so there was no issue with the wire size he initially selected. The MCA ...
JRaef's user avatar
  • 14.9k
19 votes

How to get rid of CO₂ in a house with A/C in hot summer?

That's a really high CO₂ level. You need to figure out what is causing it and fix that, it's not normal. Gas fired appliances with leaky vents are the most likely suspects — hot water heater, dryer? (...
jkf's user avatar
  • 348
19 votes

Preventing auxiliary condenser jug overflow in a portable air conditioner

Avoid 1-hose portable units at all costs. Those units are weirdly popular and trendy... and this is a mistake because of their horrible efficiency. This is not bigotry. This is science. Even if you ...
Harper - Reinstate Monica's user avatar
17 votes
Accepted

What causes burn marks on the air handler in the attic?

The burn marks on the air conditioner air handler are from the torch the installer used to solder the copper pipes to the unit. The pipes then go the compressor located outside the unit. Most ...
JACK's user avatar
  • 79.9k
17 votes

Do I really need an air conditioner filter?

Yep... "BAAAADDD" idea. Don't remove your filters, you'll gum up your equipment. Nobody's house is "lint free". I really want the least amount of resistance in order to cool ...
Kyle B's user avatar
  • 535
17 votes

Are mobile air conditioning systems an inherently flawed design?

It's true that portable AC units have some inefficiencies when compared to other styles of units (window, mini-split, conventional). At least in the US, this is apparent when you look at newer ...
CJC's user avatar
  • 305
17 votes
Accepted

Do on-wall air conditioners, mini splits, need expert installation or water replacements?

No. It may need a refrigerant refill at some point but that's more an indication of a problem than a maintenance item. If you're asking this question, you probably shouldn't attempt it. That isn't ...
aquaticapetheory's user avatar
16 votes

Does A/C encourage mold growth

You are being sold. The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture ...
Micah Montoya's user avatar
16 votes
Accepted

Preventing auxiliary condenser jug overflow in a portable air conditioner

The device you are looking to buy is (drumroll please) a condensate pump. You should preferably also incorporate a float switch to kill the AC if the condensate pump fails to work or keep up for some ...
Ecnerwal's user avatar
  • 211k
16 votes
Accepted

Can I use a 60amp AC disconnect box for a 30amp circuit?

TL;DR Yes As long as there is already a breaker protecting the wire and equipment (which you indicated is the case), the disconnect is not there to provide any overcurrent protection but rather to ...
manassehkatz-Moving 2 Codidact's user avatar
15 votes
Accepted

Would this air conditioner setup work?

Except you are pumping hot air out of the room. You are trying to create a vacuum in the room, and nature abhors a vacuum. It will push an equivalent amount of air back into the room via every ...
Harper - Reinstate Monica's user avatar
15 votes

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

See other answer for how to test for actual efficiency gain, but you're basically cooling your output coil with a swamp cooler. In commercial settings it's called a free cooler. Water is either ...
K H's user avatar
  • 2,268
14 votes

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

Disclaimer: This question is about Air Conditioners. The "You" discussed below is an air conditioner owner. This answer is not about heat pumps, which are a different class of equipment (...
Harper - Reinstate Monica's user avatar
13 votes

If an AC guy checks a system and finds it 100% out of refrigerant, what is the correct next step?

I had an AC guy say "your system is completely empty", and he had to schedule a follow-up. Then, the next day, the same guy came out and said that he figured it out over-night! He had to go away ...
Leo Lansford's user avatar
13 votes

Does A/C encourage mold growth

It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is ...
JimmyJames's user avatar
  • 2,062
13 votes

AC related power outage (partial)? HVAC?

I'm going to slightly disagree with the other answers and guess you have an open hot conductor. Either way, the answer is the same: call the power company and report a power outage. The problem is ...
Nate S.'s user avatar
  • 6,372
13 votes

Will higher BTU A/C inverter not work in room that needs 18K BTU?

This answer only applies to inverter-style mini-splits. Short answer: Yes, you can install a 24K BTU inverter-style mini-split even though the cooling load only calls for 18K BTU, provided that your ...
MTA's user avatar
  • 11.2k
13 votes

Preventing auxiliary condenser jug overflow in a portable air conditioner

Connect the auxiliary jug differently, such that it doesn't affect the shutoff mechanism in the primary receptacle. I don't know what model you have, but you could presumably add a port to the factory ...
isherwood's user avatar
  • 135k
13 votes

Why is my air conditioner causing rapid high CO2 levels?

One possibility is that you have: a very well sealed home a heat recovery ventilator (HRV) the HRV is only on when the system is configured for heating and not when it is configured for cooling In ...
manassehkatz-Moving 2 Codidact's user avatar

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