[munstie]

With the possibility of my heat pump being dead, I've got estimates from 3 companies for a new heat pump. We mostly only use it during the summer since we have a wood stove going in winter, however we do use the heat during the 'warmer' winter months. Live in SW Ohio..

Is there a benefit to having a variable speed compressor (Trane XL18i) vs the single stage (XR16) in my situation? Worth the ~grand difference in price to upgrade? Both would be paired with the TEM6 variable speed air handler.

Oh, and the load calculation said my house is right at 29,000Btu, just right for 2.5 ton, but the XL18i is 2 or 3 ton.. is it ok to go 3 ton, or will that stress the unit since my ducting is only rated for 2.5 ton?

 

[user_12345a]

Variable will have high repair costs - only worth it if it heats better in very cold weather, being able to ramp up and keep the supply temp up like the mini-splits do.

I think carrier has one which does it, as does rheem. Not sure how the others operate.

If you want to oversize to get more heating capacity, 2-stage or variable can help mitigate the negative effect on cooling/dehumidification performance.

 

[munstie]

So what you're saying is since I use it mainly for cooling, I should be fine with a 2.5ton single stage?

 

[user_12345a]

If the old 2.5 ton cooled fine and the load calc indicates 29k btu is needed, you shouldn't get something bigger.

The bigger unit isn't an upgrade unless it's for heating capacity.

And to make a real difference for heating you would probably have to upsize by a least 1 ton, enlarge the ducts to get proper airflow.

A member here (bob sanders) put a 2-stage 4 ton unit into a house needing only 1.5 to 2 tons of cooling and had excellent results -> dramatic reduction in heat strip use. But I believe he also spent a lot of time and money upgrading the ducts to get proper airflow.

Single stage oversized is lousy for dehumidification.

Heatpumps for sized for cooling fall short for heating in heat dominant climates -> more heating capacity is needed than what's needed and capacity drops as it gets colder outside.

 

[munstie]

Sounds good, 2.5ton it is! Thanks

 

[user_12345a]

something potentially misleading in previous post -> 2-speed/variable is beneficial when it comes to cooling, but it's mostly comfort not saving energy and oversizing it defeats the prupose. (unless it's being oversized for heating)

make sure that for a 15/16 seer unit they give you the right coil and use a air handler with an ecm motor. seer maxes out at around 14.5 without the ecm motor at leas to limited knowledge, things may have changed.

There's no hard limit, but the manufacturers do certain things to get the higher ratings -> the time may come when standard units can hit 15/16 without anything fancy, it's all in how the stuff is engineered, coil sizes, etc.