Another Air Conditioner thread - but this one is home A/C

[Spittybug]

My upstairs unit (~2.5 tons IIRC) has needed a little Freon help each year for the last few. Not a big deal, a little boost and I've been good to go. I've been hearing horror stories about the cost of Freon lately since all of the laws lowering the production have kicked in. Since my unit is about 14 years old, it's about time to replace him anyway. Current unit is 12 seer. The downstairs unit is fine, same age and 4 tons.

I have a hard time holding below 80* upstairs, so I know he needs a boost. So, for anyone in the audience with professional or consumer experience to share, I'd like to hear....


what is the 'break point' for cost versus seer rating?
any particular brand to get, or avoid for that matter? My current units are Amana.
is there a meaningful price decrease after the summer months? Supply and demand......
anything else?
what kind of price am I looking at?



Being this is Houston, our A/C is on about 9 months of the year and our electricity price is as cheap as anywhere.

Thanks.

[NightFlyer]

Have you considered a central air system?

Personally I've been thoroughly disappointed with all the recently manufactured portable/window units that I've tried.

[Bitsyncmaster]

Just had the same with my house last summer. Old unit was R22 and 16 years old. Turned out to be the attic air handler was leaking (evaporator). The estimate to rebuild it (new parts are NA) was almost the same as a new unit. So the full installation of a cheap new system cost me $4500. All new systems us R410A. The unit I got was a comfortmaker brand which the AC contractor could get discounted. Think both my units are 2 ton. The downstairs will probably need replacement soon. Mine is a 13 SEER unit. Since the average life of home AC units is 15 years I could not see paying a lot more for a little power saving over that 15 years.

[dmc6960]

Have you considered a central air system?

Personally I've been thoroughly disappointed with all the recently manufactured portable/window units that I've tried.

Did you look at the sizes he mentioned? 2.5 ton and 4 ton are NOT sizes you'll find a window unit in. That IS central air.

I recently fixed some AC problems on my in-laws system. Evaporator ended up icing over due to low airflow over the evaporator. The low airflow was caused by a combination the blower fan set too low, and several very large leaks in the ductwork I discovered.

The outlet from the upstairs evaporator unit, is it warm, cool, or frosty? (remove a little bit of insulation right outside of the air handler if its still perfect, see if the condensation freezes). This will tell you a lot about how the system is functioning.

[Spittybug]

The system has a very small leak in it somewhere. For the last couple of years it has needed to be topped off. Since the Freon price has skyrocketed and the system is as old as it is, I'm just weighing the options.

The attic has had an extra foot of insulation, the ductwork is well insulated and we even have the reflective paint on the underside of the rafters. Attic is definitely cooler as a result. The air coming out of the ducts is cool, not frosty. With our crazy heat down here, we're always pushing the envelope!

I'm not sure that the higher seer makes sense here. We run the upstairs unit so that it is almost always on, dehumidifying and tackling the load. The higher seer units achieve some of their economies (as I understand it) by having a variable speed compressor. Not sure that would ever get used here! Still learning though.