[Slammed01]

Looking for ways to help keep 2nd story cooler, upstairs rooms get hot esp over garage. Anyone have the above? What are your thoughts?

Had a hvac tech come over and recommended the quiet cool pro 4.8 and 2 gable attic fans for our 2100 sq ft 2 story. Fan was $1700 and 2 attics was another $1000.

Also the zone 2 upstairs thermostat is in our master bedroom, which can be 5-10 degrees hotter/cooler than our daughters room over garage. He said we could love that as well, thoughts?


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[user_12345a]

Possible pitfalls of whole house fans - from someone who has never owned one...

1. They can bring in humidity during the cooling season and end up costing more in a humid climate.

They can't be used with ac - the air outside at night may be cool, but is humid in a lot of climates. Humidity is a good part of the cooling load; minimal savings in hot humid weather.

The overnight temp would have to be 68 or lower to make a fan provide much real cooling; in very hot weather, unless u live in a desert where it gets cold at night, the fan won't do anything but bring in lots of humidity. Would be better off just keeping the house sealed.

2. Heat loss to the attic in the winter, leakage

3. Risk of having appliances backdraft.

The fan puts the house under negative pressure - can pull carbon monoxide into the house from water heater or attached garage.

 

[user_12345a]

Also the zone 2 upstairs thermostat is in our master bedroom, which can be 5-10 degrees hotter/cooler than our daughters room over garage. He said we could love that as well, thoughts?

Insufficient insulation or supply can cause that problem -> extra heat coming in from the garage.

Without spending lots of $$$ there's nothing u can do to fix the problem. would have to rip garage ceiling down and sprayfoam.

u could patch it with a window unit in that room.

 

[Slammed01]

Insufficient insulation or supply can cause that problem -> extra heat coming in from the garage.

Without spending lots of $$$ there's nothing u can do to fix the problem. would have to rip garage ceiling down and sprayfoam.

u could patch it with a window unit in that room.

We are in Northern Ca as well. Both rooms besides master get hot due to hot air rise from downstairs since it gets trapped in hallway at top of stairs. Window units aren't an option, toddlers in there and rather keep locked window

 

[user_12345a]

Check for proper attic insulation and ventilation before you spend big bucks on attic fans.

Does the house have one system or two?

For heat to rise up to the second floor, it has to be warmer downstairs than up. Otherwise the convection current between floors can't happen -> need big temp differences to begin with.

Having a hot attic above, possibly skylights, hot garage below a room contribute to temperature differences.

Insufficient supply, an unbalanced system (not enough supply in certain rooms, etc), other performance problems greatly compound the problem.

It's possible to fix a problem like this but potentially expensive depending on what's wrong. The master bedroom may be oversupplied or the rest undersupplied - or there could be something else going on.

You have to identify the problem rather than just throw band-aids at it.

The whole house fan is an expensive patch; it may be a good idea to get one to reduce a/c use and save energy by cooling with outdoor air exclusively when it's cool enough at night, not to fix a balancing problem.

 

[jimn]

A whole house fan works on where it gets cool at night
And the humidity is low. I have one and I like it because I don't like to live e in a closed house all summer . I enjoy open windows. A whole house fan requires you open windows in every room you want cooled off so if for some reason you fear a properly installed window air conditioner (where you use brackets and screws to hold the Window sash against the AC then and while house fan is not for you . How about a mini split for the garage room. Safe, quiet and it will solve the problem better than attic fans. Before investing in attic fans you should have the static attic ventaltion checkes

 

[Slammed01]

A whole house fan works on where it gets cool at night
And the humidity is low. I have one and I like it because I don't like to live e in a closed house all summer . I enjoy open windows. A whole house fan requires you open windows in every room you want cooled off so if for some reason you fear a properly installed window air conditioner (where you use brackets and screws to hold the Window sash against the AC then and while house fan is not for you . How about a mini split for the garage room. Safe, quiet and it will solve the problem better than attic fans. Before investing in attic fans you should have the static attic ventaltion checkes

House was built in 1995 I guess I should add, I don't mind opening windows and not humid here usually. Cools off at night/mornings. Even if I can run for a bit to cool house down. I would need 2 window AC units and it's just not pleasing to the eye. Don't want to invest to cool off the garage but I'm sure my truck would appreciate it!

 

[Slammed01]

Check for proper attic insulation and ventilation before you spend big bucks on attic fans.

Does the house have one system or two?

For heat to rise up to the second floor, it has to be warmer downstairs than up. Otherwise the convection current between floors can't happen -> need big temp differences to begin with.

Having a hot attic above, possibly skylights, hot garage below a room contribute to temperature differences.

Insufficient supply, an unbalanced system (not enough supply in certain rooms, etc), other performance problems greatly compound the problem.

It's possible to fix a problem like this but potentially expensive depending on what's wrong. The master bedroom may be oversupplied or the rest undersupplied - or there could be something else going on.

You have to identify the problem rather than just throw band-aids at it.

The whole house fan is an expensive patch; it may be a good idea to get one to reduce a/c use and save energy by cooling with outdoor air exclusively when it's cool enough at night, not to fix a balancing problem.

Thanks! Yea the 2 rooms closest to unit get the warmest. Not sure if ducts have been cleaned since 96' when house was built as I'm 2nd owner.

AC dude offered to move thermo for free so wanted thoughts.

 

[yuri]

If you can install a ceiling fan in the upstairs hallway it will help blow the heat down.

Convection is going on all the time as heat naturally rises and when you cook etc and have warm people downstairs it starts. It does not stop and start. The ceiling fan will help push air down and that may help.

If you can find a tech who can balance the ductwork with a velometer/anemometer which measures the air speed = (cfm) you can move more air into the hotter rooms. Houses are never balanced when new. I have seen LOTS of cool air going into walk in closets/bathrooms/other places where it is not needed as much. I have a small UEI anemometer and my company has a big one like in this pic. I go and map out the vents upstairs and record the readings and start throttling down the less necessary ones and watch the increase in other rooms you want. Then the tech needs to check the freon pressures as you cannot slow down the air too much or upset the balance of airflow or the AC coil may freeze up.

Point being he can rob peter to pay paul and take air from some vents and push it to others and balance the system. Problem is finding a tech who knows how or cares or does this work. Talk to the service manager at different companies and see who does this work. If they don't know what a velometer/anemometer is then hangup.

I would get shades for the windows and you can get some with tin foil built in that blocks heat and light better. Get the vents balanced B4 buying fans or adding mini splits.

 

[supers05]

I concur. Whole house fans are an option, but will probably not solve your problem.

If the balancing doesn't help (enough), a mini split is a great option, as you can get indoor models that blend in. (A mirror or ceiling cassettes for example)

Cheers!

 

[user_12345a]

If you have the air handler in the attic, you can add/resize ducts to deal with under supplied rooms.

If the two rooms get far more sun than the master there will always be a temperature difference,