Upstairs/Downstairs balancing

[gbynum]

Our daughter and son-in-law are buying a new home in an area with multiple substantially identical homes. Foundation is poured, but that is it.

Friends of ours live there now, and have only one real issue, which is common per their conversations with residents of other homes.

These are small homes, well insulated, 2 story, about 1300 sq-ft. As would be expected to some extent, heat rises ... downstairs is cooler in winter, warmer in summer. The physics is understood<g>. The homes have "2 ton" heat pumps, brand and ratings unknown (but I can get that). Dollars being dollars, I'd bet on the lowest cost units available that meet SEER requirements.

What are the most practical economical methods to better control the variation.

If they are really efficient, and if the thermostat and system supports it, a CIRC mode seems good; she has some allergies, and the better dust/pollen collection would also help. The engineer in me would dream of a diverter which sends more down in heat mode, more upstairs in cool ... but I don't know if that exists.

They are VERY frugal ... and would cut down thermostats when they leave ... the recovery in winter is something I need to explain, or get a good thermostat which understands those things and doesn't turn on heat strips JUST because the setting increases by 6 degrees at 4 pm when outside is 60 degrees ... <g>

As I understand it, these homes were designed by an architect firm for low construction and energy costs ... so few frills are there, but if construction is not impacted, they've been told they can add "stuff" at little over material costs.

What do I want to recommend to them?

Thanks

[comfortdoc]

If this house is not yet built, insist the HVAC system be sized and designed properly. Then have someone monitor installation to be certain it is installed per design.

I have a two story house. Without adjusting anything, my 2nd floor is a couple degrees cooler than the first (with the system on). It is the way the ducts are designed. I want the 2nd floor cooler since we sleep there. I can adjust the louvers in the rooms and change that dynamic slightly if I choose. It is all in the design and install.

[Kevin Weaver]

a 2 thermostat electric zone system will do wonders.

[gbynum]

comfortdoc and Kevin ... THANKS for the quick replies.

I should have been a little more explicit to start, but wasn't. This is an ex-REAL BAD neighborhood that is being redeveloped for economically challenged folks. They made a push to some local churches to get some middle class folks to buy. These are 26x26 identical (well, 2 plans actually) and all design work was done by "professionals" ... I don't know where the evaporator is, but all ducting is in the 1st floor ceiling, 2nd floor floor. They are on crawl spaces, not slabs, but, probably for $$, chose not to run any ducting there. I am darn sure that zoning won't fit the picture, and I do understand it, my home is zoned. I believe the structure allows for one supply and 1 return; I don't remember where the return plenum is, but likely in or really near the stairwell.

I do not like to have THEM adjusting registers ... but that may be what happens. Restricting flow seems to me as likely to cause problems.

I guess I'm asking the impossible, Buick performance for a Yugo price, but I'm not really, just a way to minimize what existing owners have identified. I'd bet (BUT DO NOT KNOW) that a local tech school's HVAC class does the work ... without supervision?.

Thanks!

[George2]

The HVAC guy will normally run all 6" supplies. I would ask them to increase the supplies to 7". This will cost very little additional (just for the materials.) The kids can adjust the dampers as needed.

The return is probably going right off the side of the furnace. Have the HVAC guy elevete the unit on a box (to reduce the noise) with a 4-5" air cleaner on the side (if room allows) or they may need to put it under the furnace.

[motoguy128]

The HVAC guy will normally run all 6" supplies. I would ask them to increase the supplies to 7". This will cost very little additional (just for the materials.) The kids can adjust the dampers as needed.

The return is probably going right off the side of the furnace. Have the HVAC guy elevete the unit on a box (to reduce the noise) with a 4-5" air cleaner on the side (if room allows) or they may need to put it under the furnace.


+1. Just a very small simple change can make all the diffrence.

I installed higher quality supply regsters and added 2 dampers and completely rebalanced my downstairs and increaed airflow by about 10% overall.

Upstairs I added 2 supply registers and 4 dampers and cut the noise in half and increased airflow by about 20%.

With a well insulated home, 2 tons in a 2 stroy 1300sqft should be plenty of capacity. Definitely oversize the upstairs ductwork, then in winter you'll just have to partially close some registers upstairs, or keep the downstairs a little cooler.

Better is a zone system, but it sounds like this is a low cost development. Upsizing the ductwork is the best option.

[motoguy128]

The engineer in me would dream of a diverter which sends more down in heat mode, more upstairs in cool ... but I don't know if that exists.



They do. It's called a damper. IF the systme had 2 sperate main trunklines for upstairs vs. downstairs, you could simply put a damper on each, upsize the ductwork a little (mainly upstairs) then balance the system manually. You can also instead use powered dampers and use a zone controller to do the same thing... or even cheaper, (a poor mna's zoning) use a powered damper and a seperate thermostat upstairs to clsoe the damper paritall when the thermostat is satisfied.

But it's all in how the ductwork is installed and sized.


DO these have a furnace or heat pump? IN SC, I'd expect a heat pump. IF so, DO NOT USE SETBACKS WITH A HEAT PUMP. Ever. It will increase your electric bill.

[George2]

They do. It's called a damper. IF the systme had 2 sperate main trunklines for upstairs vs. downstairs, you could simply put a damper on each, upsize the ductwork a little (mainly upstairs) then balance the system manually. You can also instead use powered dampers and use a zone controller to do the same thing... or even cheaper, (a poor mna's zoning) use a powered damper and a seperate thermostat upstairs to clsoe the damper paritall when the thermostat is satisfied.

But it's all in how the ductwork is installed and sized.


DO these have a furnace or heat pump? IN SC, I'd expect a heat pump. IF so, DO NOT USE SETBACKS WITH A HEAT PUMP. Ever. It will increase your electric bill.

Sorry, I do not know how to highlight the statement I want to address.

Re: running the seperate ductline (poor mans zoniong.) Reminds me when I bid a house (ranch w/a walkout basement) for a "friend". I bid it with a sepeate duct to take care of the basement and to make it easier to zone (if need be) in the future.

They (or the builder) took the cheaper bid.

10-4 on NOT using a setback with a HP.

[precision hvac]

HVAC guy probably has a contract w/ builder. Pretty rare to get anything modified by buyer until they are moved in. I did tracts for 20 years- any mods to system had to be run through the builder/contractor, not the sub.
Just FYI.

[ar_hvac_man]

If zoning, or two systems, is out of the question Id oversize the ductwork some to allow for some degree of dampering at the registers.

[genduct]

Put the HP on the second floor in the thermal envelope (best) attic not as good OR make sure you have a single, central, high return grill with tranfer ducts for return from any space that has a door that can be closed.

This 100% high return will mitigate some of the natural "stack effect' but will not make up for non working supply diffusers.

[gbynum]

Thanks to everyone. Yes, DEFINITELY a tract development. I talked to our friends who were 1st in the neighborhood and other than security worries, the HVAC balancing is the only issue they have. They say it is pretty quiet, but I'm so hard of hearing that _I_ would not have known it if there was a 747 running in the room<g>.

According to them, it is heat pump. I have not personally confirmed that, but I've told the kids to pay upgrade if not ... electric furnace is not the way to go, even with the low electricity (Duke Power) prices. Gas is not available.

SO ... given what I've heard here, ask for ductwork upsized, better and more easily tuneable registers ... and I need to EMPHASIZE to NEVER restrict both up and down, one must be fully open.

I don't know what's cheaper than builder Goodman, but bet they find it. The good situation is that a builder they know, not the original guy, is doing it, to approved plans.

Again, thanks everyone!