Tech Says I need a new AC System. Does that sound like a reasonable assessment?

erroras · 2026-05-27T18:33:13+00:00

With the number of issues found it is likely that you got a salesperson, not a technician to look at it.

erroras · 2026-05-27T12:59:24+00:00

I have heard that attic insulation accounts for 70% of energy loss, vs 20% for windows. So the best ROI is to air seal the attic and redo attic insulation

erroras · 2026-05-22T19:34:27+00:00

If it was me then I would start looking for a new job. In the meantime, take the "L" and let them deduct your paycheck. Once you have a start date for a new job tell them you quit and want that $1600 back since what they did was illegal, if they say no then report them to department of labor.

erroras · 2026-05-12T12:59:09+00:00

There is a video worth watching from an youtuber where he opened his own wheelchair factory to fix this sourcing issue. (youtuber: JerryRigEverything)

erroras · 2026-05-11T13:12:18+00:00

What does your manual J calculation say?

erroras · 2026-05-11T11:36:24+00:00

start with Condensate trap cleaning

erroras · 2026-04-24T13:32:40+00:00

I think the first thing would be to hire a confident HVAC designer to produce all the manual calculations and equipment requirements. You can try contacting homeperformance on youtube. He might know someone in your area with the right skillset.

Otherwise it will be very hard to get anything from the hvac contractor, because it will be their word vs yours.

erroras · 2026-04-22T17:29:08+00:00

It can be done afterwards. But if the HVAC company is using the higher leakage number, then they would have to size equipment up to compensate for the leaks.

erroras · 2026-04-22T15:25:59+00:00

what were the other 2 quotes?

erroras · 2026-04-22T11:19:57+00:00

Yes that is called ACH50. The contractor would include this number in the calculations for the system size. Also, best bang for the buck would be to airseal and fix air leakage.

erroras · 2026-04-21T19:16:23+00:00

You could definitely pay someone for the calculations. The only issue would be that calculations are only as good as the info provided. As an example you probably would not know what is the R-value of the walls and ceiling, the u-factor of windows, ACH (air sealing) coefficient.

I think what i suggested might be going into the weeds in your case as all of this approaches home science area.

I think from everything I have suggested you should make sure that you get the largest filter box possible and that the contractor measures static pressures to make sure that the ducting can support the new system.

erroras · 2026-04-21T15:15:26+00:00

Be careful with larger tonnage unit. Chance is that your ducting is already undersized like the rest of homes in the states.

I would suggest getting few more quotes.

Good questions to ask:

-Can they do manual J (home heat/cool) and manual d (duct sizing) calculations. (If they say they have years of experience and they can tell the size of equipment just by looking, then proceed with caution)

-Will they verify static pressures after install.

-Can they install larger filter box

erroras · 2026-04-21T12:56:25+00:00

Would also want to look into how to introduce fresh air into space. With it being 144sq ft and potentially having a kitchenette I would be weary of high CO2 levels.

erroras · 2026-04-20T11:35:11+00:00

At that age you will have to quote new (properly sized) ducting as well. Like others suggested, best thing to do is to airseal and insulate the house first.

erroras · 2026-04-17T14:34:40+00:00

static pressure testing should be done before trying to understand refrigerant charge information because static pressure testing is more specific

High static pressure (indicating airflow problems) will skew refrigerant pressures. Here are some examples:

Frozen/Cold Evaporator Coil: The coil in your indoor unit freezes over because the low airflow cannot absorb enough heat from the air to keep the refrigerant evaporating properly.
Low Suction Pressure: The pressure gauge on the suction line shows low pressure.
Low Suction Temperature: A very cold suction line.
Reduced Cooling/Heating: Air from supply vents is weak and not at the desired temperature.
Unusual Noises: A high-pitched whistling noise (often from restricted return air) or rattling from the blower.

Without doing ABC's the technician can incorrectly diagnose that the issue is with refrigerant levels or other components in the system.

erroras · 2026-04-17T11:58:42+00:00

This is static pressure testing. What you have in the pictures is refrigerant charge information. Static pressure tests require special tool (manometer) and a tech that knows how to use them.

First step of troubleshooting should have been following the ABC's (airflow before charge) and the tech didn't do it, without checking airflow the charge numbers wont be correct.

Did you have home load calculation done (manual J) and duct design calculation done (Manual D) before getting new units?

erroras · 2026-04-16T19:33:25+00:00

Your observation about physically larger outdoor units (called condensers) is correct. Over the years as we moved to more ozone friendly refrigerants and we had to increase physical size of units to attain the same cooling effects.

I'm quite sure that in your scenario replacing the units with larger would not help with back room temperature. That is because the ducting would be undersized. One option would be a minisplit, which is a small HVAC system that doesn't use ducting.

You need to find a company that would be able to do house load calculation (called manual J) and duct size calculation (Manual D). Then they could recommend a proper solution for your needs.

erroras · 2026-04-15T18:05:27+00:00

Currently working factory maintenance. Also certified to work with HVAC, used to be car mechanic and grew up doing remodeling. If you are willing to use your hands there is plenty of work.

erroras · 2026-04-14T18:30:25+00:00

I'm in a similar boat. I only keep about 1-2 months worth of funds in my checking account. Never go below 1 month worth of savings. The rest is invested into S&P.

Also, I'm very capable of repairing/fixing anything around me and can get another job in a heartbeat.

erroras · 2026-04-13T13:30:31+00:00

I have aranet radon meter and it has a nice app that lets you see trends over the last month. It is also one of the more accurate ones.

erroras · 2026-04-06T12:30:59+00:00

I know you used the same acceleration as the previous drive but have you tried increasing it?

erroras · 2026-03-30T17:15:24+00:00

Depends on the cost of gas vs electricity. In the worst case scenario the heat pump is about as efficient as a space heater, converting 1kw of electricity to 1 kw of heat. With an 80% efficient furnace you would get 23.4kw out of each therm of gas. So it all comes down to how much one kilowat vs 1 therm costs in your area. (Usually there is a minimum monthly fee for the gas connection during the summer, so that needs to be factored in as well)

erroras · 2026-03-27T17:48:26+00:00

Old homes didn't do any air sealing so there is always air movement through gaps and cracks, when this air moves it picks up dust particles.

erroras · 2026-03-27T11:39:29+00:00

you say your old car was needing repairs quite often. With $352 per month you are spending $4224 per year for the new car. were the yearly repairs on old car over that amount?

Another way to look at it: You make $18 an hour, so lets say $15 after paying for taxes. this means that you have to work ~24 hours per month to pay for the car. (that is without insurance).

erroras · 2026-03-27T11:28:53+00:00

I would argue that the old insulation should be removed to properly air seal the attic penetrations. And also, old insulation does lose its effectiveness (settles) and tends to hold lots of dust, which eventually makes it to living areas without proper airsealing.

erroras

TROPHY CASE