Can I add a second zone to one hvac system?

[The motor guy]

I live in a townhouse and the thermostat is upstairs, so there is only one system for both floors. The problem is the house is on stilts so there isn't any insulation below the first floor and the cold goes straight through the floor and makes the downstairs 5-7 degrees cooler than the upstairs. I would like to add a second zone downstairs to run off the same system if that's possible.

 

[walterjay]

Maybe. Have a professional HVAC pro look at it.

 

[NormanBuntz]

Yes, but it ain't cheap and it's not always the most reliable in residential use. My four ton heat pump runs two zones, but I'm on my third zone control board in 16 years. Plus mechanical dampers in the ducts are finicky. It's doable though.

 

[The motor guy]

How about two separate systems? 10 grand? It wouldn't have to be that big of a system. It's only like 800 sq ft per floor and the ceilings are only about 10ft tall.

 

[The motor guy]

I could probably wait until this system takes a dump then work out a deal for two separate units.

 

[ammolab]

Adjust/close the upstairs heater vents so most of your heat goes downstairs.

Enough heat will rise up top naturally to supplement what comes out of those restricted vents.

 

[The motor guy]

Originally Posted by ammolab
Adjust/close the upstairs heater vents so most of your heat goes downstairs.

Enough heat will rise up top naturally to supplement what comes out of those restricted vents.



I tried that, it doesn't seem to make more go down to the downstairs vents, all it does is make the vents whistle loudly upstairs

 

[CharlieBauer]

I would be tempted to install underfloor heating since based on your description the floor will still be the coldest part of the room even with more hot air.

 

[walterjay]

Have a couple of HVAC companies look at it and get their take and estimates. Shouldn't cost anything and then you will know what can be done and what it will cost.

 

[user52165]

Is it possible to add insulation down low?

 

[AZjeff]

Mini split heat pump. Perfect solution.

or

Have you tried having the registers balanced? Closing the upstairs down to put more warm air out the downstairs registers.

 

[CDX825]

If you can easily get at your main trunk zoning wouldn't be a problem. We install arzel zoning systems on existing duct work to zone a non zone system and it works great.

 

[WyrTwister]

Originally Posted by user52165
Is it possible to add insulation down low?


Good idea .

 

[WyrTwister]

Originally Posted by AZjeff
Mini split heat pump. Perfect solution.

or

Have you tried having the registers balanced? Closing the upstairs down to put more warm air out the downstairs registers.


Also a good idea . Do both , mini-split + insulation .

 

[dtownfb]

By "stilts" do you mean it has a crawl space; or "stilts" like a house on the beach? Also what kind of heat do you have? Any changes to your heating system is going to cost $$$. And will add to your heating bill.

I would start with how can you insulate under the first floor to stop the cold. If you have access under the floor, adding insulation in the floor joist will solve most of your problem and not break the bank. Plus it's something you can potentially do yourself.

 

[AZjeff]

Originally Posted by dtownfb
If you have access under the floor, adding insulation in the floor joist will solve most of your problem and not break the bank. Plus it's something you can potentially do yourself.


I've been a DIYer my whole life but this is something I'd probably pay to have done. Yuck.

 

[Andrew1972]

Are you solutioning this yourself? I only ask because:

1) Heat rises
2) Adding more HVAC is not addressing the core issue of cold floor since heat again will rise.
3) You always insulate first before touching the HVAC system as general rule.
4) Home on stilts at my in laws on oceanfront home led them to two things in major renovation: radiant first floor heat and also using spray foam insulation as otherwise the floor would be always cold.

 

[alarmguy]

When you said that you tried to close the upstairs vents to force more air downstairs that it didnt seem to help.
Its quite possible someplace in your ductwork there might be a "balancer" flap (lack of better word at the moment" So there maybe a internal "flap" in the duct feeding the downstairs and it might be slightly closed to force more air upstairs which would be typical for summer time airconditioning.
Anyway, check the ductwork where ever you can, you may see a lever sticking out someplace that opens and closes the airflow, more or less lets you adjust it.

Im assuming your have made sure the floor is properly insulated.

 

[The motor guy]

Yeah downstairs there is only one vent that blows good. There are only three vents downstairs btw. Also the vents upstairs all put out tons of air.

 

[PandaBear]

Can you run a window unit? or add a mini split then gradually replace worn out / aged AC to mini split system?