I have a 3-story townhouse with a gas furnace and central air. The compressor is dead. I’ve already tried having a hard starter added but it still isn’t working. As far as I can tell, since the unti is 14 years old, it makes the most sense to replace both parts of the split system. According to the HVAC guy who told me it was finally, irretrievably dead, the unit is slightly large for my current house. Here are my questions:
Am I correct that it is best to replace both components at the same time to improve efficiency?
Any recommendations on the best system?
I have been reading about SEER ratings-how high should I go with the ratings? Is 13 enough?
I assume I should get several estimates but can I do this over the telephone once I decide on a system? (This is what I did when I replaced my hot water heater-I chose a model then went with the best estimate).
Should I have each estimator make an in-home visit to assess what size unit I actually need, especially if the current one is too big, or should I stick with the size that has worked well for me so far?
Ideally, I would like to do this ASAP, before the hot weather, and it is nearly impossible to get free time to have several people come over to give me estimates. In addition, I have other workers coming on 4/18, so that would be an ideal day to have it installed if I have chosen a system and a contractor by then.
Finally, I do have a 2-year service contract on my current HVAC system (it saves money and gets me Saturday service). Would it be wise to buy the new unti from them also?
I would seriously doubt anyone could give you an accurate estimate over the phone for a new system. Unlike a hot water heater, there are a ton of variables.
I would also want to talk to the guy face to face to gauge my faith in his abilities.
Figure your tonnage requirement. Rule of thumb is 500 sq. ft. = 1 ton. Do some prechecking on the internet for the major brands like Carrier, et al., then have at least three a/c contractors give you bids.
I just got through doing this, and I am soooooo glad I did.
Check if any any place like a utility company is given you money to install certain high efficiency models. That may allow you to have a better unit for a better deal, using less power over the years.
Our tenant installs AC units for a living. After a little brain-picking…
15 is pretty much a rock-bottom SEER rating now. Most of the units he installs are rated at 16 or 18, with the occasional 21. 21 is about the best efficiency available now.
Most of what he installs is Carrier. They also do a lot of Mitsubishi Mr. Slim ductless units - this is a niche product great for modernizing old buildings where you can’t punch big holes all over for ducts. The coolant piping or “lineset” for these can be run within the walls, with just a slim air handler mounted to the wall or ceiling.
Scroll compressors are where it’s at these days. They run quieter than reciprocating piston compressors and because there’s only one moving part, they tend to run longer before breaking down.
A newer wrinkle in compressor design is multispeed or multicompressor. It used to be that an air conditioner was either on or off. Now, there’s a range of “strengths” available. The multispeed designs run the compressor at variable speeds - slow and efficient on moderately warm days, on up to full power for hot days. This also provides a reduction in noise. Multicompressor units have a small efficient compressor for regular days and a large “full power” compressor for hot days. Similarly, newer units have a multispeed drive for the blower. The primary benefit to this is less noise in the house. You’ll probably need to replace the furnace as well to get a multispeed blower.
Definitely have estimators come to your home. Its not possible to get a good quote together over the phone - there are seemingly five thousand things they need to look at, measure and otherwise assess to properly size a system to the home like roof color, amount of insulation, west- or south-facing windows and exposures, space availability and/or restrictions, existing electrical service to the outside unit, etc.
Anyone who quotes over the phone will be the guy who surprises you with upcharges like “Oh, you’ll need to upgrade the electric line from 50 amps to 60 amps for this unit. We can take care of it for another $500 so you don’t have to call en electrician and wait for them to come out.” Next thing you know, you’ll be paying more than what the reputable guy would have quoted as a firm price and who either added a more realistic $150 for the electric upgrade into the quote, or kept the 50 amp circuit in mind and selected a different unit entirely.