2 Zones or 3 for new House with finished basement?

[eap]

I am looking at buying a new construction home (not built yet).

The house is roughly 3,000 square feet (main floor and 2nd floor), plus we are finishing the basement which will add about 900 more square feet. The basement is mostly above ground due to the grade (walk-out basement).

In determinning the HVAC solution, we are pretty much decided on the Carrier Infinity, variable speed furnace, 96% AFUE, 14 Seer (with Infinity Controls). We live in the Philadelphia area, so we get hot humid summers, and the winters can get cold for about 2 months.

The builder in discussion with the HVAC contractor has suggested that we use an electronic damper to zone the 2nd floor separately (meaning the 1st floor and basement will be together).

In other words, there will be one unit, with a thermostat on the 2nd floor (controlling the bedroom areas); and a thermostat on the 1st floor (controlling both the basement and the first floor).

My question is, why did they not suggest 3 zones (separate thermostats for each floor)? Will it cost more to do that? If so, how much should it cost?

Does it make sense to do 3 zones -- or will that require a larger unit?

In case it makes a difference, note that I will have as part of the finished basement a 16 x 20 home theater room. This will be a separate enclosed room within the finished basement. So I will want decent comfort levels in the basement.

Also, we don't want to go for 2 units -- which would cost more, plus it would cause more duct work in the basement ceiling, limiting other options (like lighting, etc.).

[docholiday]

You know, no matter what anyone says, zoning is not the end all cure all. It is a less expensive means to an end. The best solution is two systems. BUT if you are not going to go that way, then definately zone it. Just dont expect the performance to be the same as two systems.

The problem in Philli is not the hottest of days, its the mild, part load days. Two systems will help in these cases far better than a zoned system.

I would not zone the basement, Unless it's a 9 foot ceiling, finished, maybe even walk out. The load is so much different than the rest of the home that it will cause more trouble than it's worth. If it were me, the theatre room would be on a mini split.

[eap]

Thanks. The basement ceiling is 9 foot when NOT finished. When it is finished, with the drop ceilings, hiding the ductwork, etc. -- it will be 7' 8". It will be walkout (but I think partially underground on the front part of the house).

With the above info, do you still think the basement should NOT be zoned on its own?

Can you explain what you mean about the "load being different" for the basement? Isn't it about the same for each floor (roughly 1000 sq. feet on each floor). Or is load different from square feet?

What is a "mini-split" -- and will that work with the 2 zones that they are thinking about now?

Will a "mini-split" add to the costs?

With 2 systems, the builder said one system would be for the top floor; and one for the basement and 1st floor. So either way, my basement and 1st floor would be together. The 2 systems would each be smaller than the one unit.

I quizzed him about zoning and if the unit is big enough for the job and will it work -- they said it would. Note that it will be an "electronic damper" -- which I assume means computer controlled?

[Edited by eap on 07-17-2006 at 01:51 PM]

[dash]

Use a two stage furnace and two stage cooling ,with the Infinity Zoning System,it will work just fine ,if they size the ducts within reason.

Zone each level and the media room.

[eap]

Originally posted by dash
Use a two stage furnace and two stage cooling ,with the Infinity Zoning System,it will work just fine ,if they size the ducts within reason.

Zone each level and the media room.

So you are saying 4 zones? Not 3?

The unit is variable speed furnace. The website info doesn't say 2 stage -- not does it mention variable speed air conditioner.

Is a variable speed furnace (the blower) the same as a variable speed air conditioner? In other words, will the variable speed work with both heat and cooling -- I went to Carrier's website, but it is not clear.

[eap]

[this post deleted by poster]

[Edited by eap on 07-17-2006 at 04:39 PM]

[eap]

Originally posted by docholiday
You know, no matter what anyone says, zoning is not the end all cure all. It is a less expensive means to an end. The best solution is two systems. BUT if you are not going to go that way, then definately zone it. Just dont expect the performance to be the same as two systems.

The problem in Philli is not the hottest of days, its the mild, part load days. Two systems will help in these cases far better than a zoned system.

I would not zone the basement, Unless it's a 9 foot ceiling, finished, maybe even walk out. The load is so much different than the rest of the home that it will cause more trouble than it's worth. If it were me, the theatre room would be on a mini split.





Builder just got back to me. He indicated that they can not do 3 zones with one unit -- the maximum is 2 with the electronic dampers.

So I guess my question is moot.

[dash]

Sorry about that.

Now it's not on every post here!!LOL

Yes,4 zones,Carrier Infinity zoning,two stage gas furnace and two stage compressor in the outdoor unit or heat pump.


Check out Hybird Heat,gas furnace and a heat pump,operation in heating determined by gas versus electric costs,and the temperature.

Variable speed is the fan in the indoor unit/furncae,same fan for heating and cooling.

Now ,I'll be back,but I'm going out for a smoke break!!So be patient.

[eap]

Originally posted by dash
Sorry about that.

Now it's not on every post here!!LOL

Yes,4 zones,Carrier Infinity zoning,two stage gas furnace and two stage compressor in the outdoor unit or heat pump.


Check out Hybird Heat,gas furnace and a heat pump,operation in heating determined by gas versus electric costs,and the temperature.

Variable speed is the fan in the indoor unit/furncae,same fan for heating and cooling.

Now ,I'll be back,but I'm going out for a smoke break!!So be patient.


Thanks for the reply.

Hmm, in the mean time I emailed the builder about 3 zones and was just told:

"We can not do three zones with only one unit. The maximum is 2 with the zone dampers."

Not sure exactly why, but that's what they say.

Hopefully the 2 zones won't keep me too cold in the winter in the basement (or too hot in the enclosed theater room). Not worried about cooling in the basement -- heat (lack of it) always seems to be an issue with basements. But others have me concerned about too much heat in the enclosed theater room in both winter and summer.

[dash]

3 zones ,if Carrier ,is not Infinity Zoning ,though it can work if properly designed and installed ,is nothing like Infinity Zoning.


Infinty will handle 8 zones.

[comfortdoc]

How close are you to construction? He may mean 2 zones is the limit based on what he has budgeted for HVAC right now. You may be able to get other options if you're willing to pay for them. I'm not certain but I think the 14 SEER is single stage. That may also be the limiting factor on number of zones.

With that said the only concern I would have with 2 zones in the situation you gave is the theater room. As already mentioned you might want a ductless split for that area of the basement. Mitsubishi makes a variable spd heat pump that maintains it's efficiency and can operate in A/C mode down to 14 degF outdoor. Take a look here: http://www.mrslim.com/Products/Category.asp?ProductCategoryID=24 . It will work very well for that application.

[Edited by comfortdoc on 07-17-2006 at 05:15 PM]

[eap]

Originally posted by comfortdoc
[B]How close are you to construction? He may mean 2 zones is the limit based on what he has budgeted for HVAC right now. You may be able to get other options if you're willing to pay for them. I'm not certain but I think the 14 SEER is single stage. That may also be the limiting factor on number of zones.

With that said the only concern I would have with 2 zones in the situation you gave is the theater room. As already mentioned you might want a ductless split for that area of the basement. Mitsubishi makes a variable spd heat pump that maintains it's efficiency and can operate in A/C mode down to 14 degF outdoor. Take a look here: http://www.mrslim.com/Products/Category.asp?ProductCategoryID=24 . It will work very well for that application.

We are still a ways off from construction -- we haven't signed the agreement of sale yet (but might this week or next).

The upgraded unit is 14 seer; 96% AFUE; variable speed (the standard unit is 13 seer; 92%; non-variable speed). There is another upgrade to a 15 seer unit -- but it is almost twice the $$$.

Here is the info on the Infinity 96 (SEER isn't mentioned though):

http://www.residential.carrier.com/products/furnaces/gas/infinity96.shtml

He definitely wasn't referring to $$$ in saying there is only 2 zones possible -- my guess is its design or duct work placement or some other technical issue. He did say it is possible for 2 zones with "electronic damper" -- so maybe he is implying that you could get 3 zones with 2 units -- where one of the units is divided into 2 zone.

And there is an upgrade to 2 units -- for a lot more $$$.

But for some reason, with one unit, only 2 zones is what the builder will do.

So you think I might just need to make it a little cooler on the 1st floor, to keep the home theater room cool enough?




[Edited by eap on 07-17-2006 at 07:14 PM]

[dash]

Ask to talk to the builder's HVAC Conctractor,there is no reason you can't have more zones,other then signing a contract before getting what you want/need.