Closing Vents

ELM

HVAC is not my trade so please forgive an elementary question. I have just purchased a two story house and I would really like to close the vents upstairs and heat from the bottom up with the downstairs vents open. Also, cool from the top down in the summer.
Each level is about 1500 sq ft with plenty of vents and return air ducts. I have a heat pump with electric furnace.
The question is, will this overload or stress my system? I have tried running it this way and the house is much more comfortable.
The warm air satisfies the thermostat, which is upstairs, before level 1 gets warm if all the vents are open.

mdshunk

Sounds like you're due for a visit from a TAB technician (testing and balancing). Doing something arbitrary on your own may or may not help, and it may well shut your furnace down on overtemp (due to lack of air flow from the closed registers). Get your system professionally balanced, and you'll be set forever.

thom

I tell my customers to close the upstairs in the winter and the downstairs in the summer. Not fully, but enough to change the air flow. Otherwise I hear that the upstairs is to warm (summertime) and the downstairs is to cold (wintertime). T&B on a house seems like overkill.

mdshunk

Yeah, you're right. Comfort is way over rated.

ELM

How would you balance a home hvac system? Maybe dampen the upstairs ducts?

All replies are appreciated.

K2

I don't know the answer but I'm reasonably certain I've had cracked heat exchangers from overheating due to blocked vents and returns. Our area has zero tolerance for cracked exchangers and even the smallest crack away from the flame where the screws attach the exchanger are reason to red tag. Some teenager smoking dope might block vents because ,well just because.

I'd say call in a pro if you are going to change the breathing ability of the system.

ELM

Thank you for the replies so far. The one thing I am completely certain of is that the termostat is upstairs and warm air rises.
The downstairs will always be cold in the winter without an alternate heat source like a gas fireplace etc. Adding a heat source downstairs may just complicate the problem by making the upstairs even hotter etc.

I figured I may have to call a pro to give it a look but I would like to have expectation. Most people prolly just put up with the discomfort.

K2:
Logic tells me pros aren't nearly as concerned with cooling as they are heating in this situation, so I understand your answer.

thom

MD, t&b won't get you there. His problem is seasonal variance. Unless you t&b it twice a year, it won't work. Adjusting the registers is fine. You would need to close almost all the registers before you started building significant pressure in the system.

The number and size of registers on systems varies considerably in standard installations.

We don't t&b our residential systems here.

hf05

What are u talking about maybe 4 or 5 registers upstairs.Don't close the return or block it,but if this works for u go nuts.Every person is different as well as every home,this type of experimenting is great .Find what makes u comfortable theres no black or white here!As for overheating really can't see it.Unless u have registers taped or something they still pass a little air the same as your ductwork.The same would apply to your thermosta and humidistat settings,do what works for u.Having said all this ,this would be as far as u should go with monkeying with your htg/cooling system,and check filters.....

ELM

Thanks again for all the replies. There are many registers upstairs like 15 or more but many downstairs also.
My personal feeling is that I am not trying to push air somewhere it does not want to go like cold air up or warm air down and it is an easy push with plenty of vents and return air ducts. Most pros will respond that it is a bad idea to close anything and I can dig what they're saying.

But...

K2

My paranoia about shuting down vents comes from the Magic Chef horizontal/crawl space units that were installed around here in the mid 80's by the thousands. Almost 100% failure of the heat exchanger in 5 years. I had a few that cracked but suprisingly we had a few that didn't crack. I accounted the good ones to a free flowing system. We replaced them all anyway.

For years our hvac companies knew that if they drove up an 80's house with a crawler, they'd get to sell a new furnace if it hadn't been replaced already.

Most of this I know from bs'ing with the hvac inspectors down the gym.