Overwhelmed! Any help appreciated

10 years ago

Live in a coastal California city and have never needed A/C until the last few years, have finally decided I need it. Here's the dilemma: I live in a 2 story house a little over 3,000 square feet. Have a large furnace in the attic ( gas central air 13 yrs old and in good condition) but the downstairs is cold compared to the upstairs (I measured a 15 degree difference today 87 master bath to 72 downstairs).

Since it's so mild of a climate here I really don't need any heat upstairs-ever. If I could just heat the downstairs it would be fine. The opposite is true for A/C--I really never (ok maybe 5 days a year) need A/C downstairs--but since heat rises I really want A/C upstairs for the bedrooms to sleep.

So I thought of getting a zoned system (essentially first floor only for heat and second floor only for A/C) using my existing heater and adding central air. But I am so confused about that it seems there are pros and cons.

One person wants to 'dump' the excess air into an area above the staircase. Another says that's a bad idea and the excess air should go back into the system with a bypass duct. Frankly I don't know what the heck they are talking about!

Finally they all want to install different equipment. Bryant, Trane or Daikin. I've never heard of Daikin, is it any good? (I just read on wikipedia that Daikin bought Goodman which scares me).

If I had casement windows upstairs I'd probably just throw in some window bangers in the bedrooms and call it a day. But that is not an option. And no I don't want 2 separate furnaces and 2 A/Cs that is overkill in this mild climate. Winters are 60-70 daytime temperatures mostly and summers are mostly in the 70s so A/C is never needed during the day I just open a window. But nights can get a bit stuffy.

One company discouraged zoning saying just balance the ducts.

So, my questions are
1) Is zoning always a bad idea or do you think it could work in this case?

2) If I zone--how should they 'dump' the extra air?

3) I know the installation is the most important factor however are any of these brands significantly better than the others or are any to be avoided?

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Comments (4)

klem1
10 years ago
First off dumping extra air doesn't sound very well enginneered.
Much of the answers have to do with layout of the home. Considering the small amount of heat/cool needed,how about altering/adding/moving ductwork to direct bulk of heat downstairs,derate furnace btu output and call it a day? Install a mini-split (one condenser with 1-2 or 3 evaps depending on how many bedrooms) upstairs for cooling. You might even consider 1 mini-split w/1 evap in hall and use a box fan on exceptionaly hot occasions to push additional air into rooms if nessary. Retrofitting the 13 yo furnace with cooling is a poor approch with no real benifits. If you or a friend are good with carpentry,cutting a hole near the ceiling for one or more "window bangers"would take care of cooling.
tigerdunes
10 years ago
shappy

Your home is on a slab or over a crawlspace?

Tell us about your existing HVAC system.

Age, brand, size, efficiency...

And your ductwork system. What material is ductwork and its insulation rating? I assume you have ceiling supplies for upstairs. How many returns for upstairs? Ductwork to downstairs runs through a chase of some kind? It just seems your ductwork system is the starting place for complete evaluation.

Since your weather is relatively mild on average, I think both zoning or a second system is overkill.

I would like to know what dealer proposes exactly as far as air balancing between the floors both for heating and AC. Any cost estimates given?

How would you describe your home's insulation including attic and building qualities? Good DP windows?

Do you have a budget in mind?

Post back.

IMO
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shappy
Original Author
10 years ago
Thank you for the response

The house is 45 years old and built on a slab.

There is currently no central A/C, just a furnace in the attic.
I don't know how large it is, I was told it is 'large, large enough for a 3,000 sq foot house'.

I have one air return upstairs. Upstairs there are 5 bedrooms, 4 baths, so 9 registers. There are 7 registers downstairs.

The house is fairly well insulated, almost all double paned windows. The ceilings are 8 foot high so no crazy vast open spaces.

The furnace was originally downstairs and the trouble began when it was moved upstairs--the first runs off the furnace are upstairs thus massive heat where I don't need it.

I don't know what the ductwork is but the attic is insulated and all ducts were replaced in 2000.

The bids so far are $8500 - $10,000 that includes a 5 ton A/C, zoning, two thermostats, permits & HERS testing (that's about $800 worth).

Another bid was $18,000 but that was for replacing furnace with a two stage and a two stage A/C which is way overkill.

One contractor suggested just balancing the ducts without zoning and for the evening problem just opening the windows and turning on the fan! The outside temperature during the summer is generally in the high 60s (I've actually used a $20 window fans to bring in cold air and they do a decent job).
shappy
Original Author
10 years ago
Oh I forgot my budget. $10,000 max. Of course I'd like to spend way less than that:)

My main concern is getting the house comfortable and operating costs. No sense in spending that much money and finding out it costs to much to run the A/C. We have tiered electric in California. (For example, just replacing my old pool equipment with new cut my electricity bill
in half.)

I might be happy just putting in a mini-split. Are they pretty energy efficient? Everyone I've had out for estimates discourages that since I've got all the ducts for central, it just seems to me that since the temperature is so mild and there's just 2 of us in the house not many rooms are used so it seems silly to have the entire house at the perfect temperature. If the mini-split takes as much electricity as central a/c I'd just go for central then.