Roof vent information

[Mosells]

I’m considering having a roof exhaust vent installed. Is it worth the expense, solar or thermostat? Who do you recommend for this service.

[retiredguy123]

I’m considering having a roof exhaust vent installed. Is it worth the expense, solar or thermostat? Who do you recommend for this service.
I don't think it is worth the expense. But, if I did it, I would use a thermostat type. The Solar Guys are very popular, but I'm not sure if they will install a thermostat exhaust fan. If I had a roof exhaust fan installed, I would want to know how I can check to verify that the fan is actually functioning and moving air. Some people think they have a functioning fan, but it has been broken for years.

[Kenswing]

We have the solar attic fan installed by the solar guys. We had it installed in the storage area directly above the stairs. It certainly drops the temperature in the attic and is easy to see if it’s running. I just press the button to lower the stairs. I can see and hear it running from ground level.

[Decadeofdave]

It is worth it, keeps temp down and can prevent mildew in the attic.

[JohnN]

Solar Guys installed mine 10+ years ago and runs like a charm. I opted for the electric.
And you can hear it running when in the garage and feel the air moving, no problem with that.
Highly recommended.

[Toymeister]

I have more than an opinion I have facts.

Background: I had thermostatically controlled electric roof vents with a means to record WHEN the fans operate. This system operated in a designer, 2000 square foot home with existing ridge vents.

The fans operate up to 11:00 PM in the temperate months running well into the early AM in August (2:00 AM). They start from 11:00 AM to 2:00 PM.

Problem with solar:

They do not operate when you need them.

Solar electricity it not binary. In other words the 20 watt panels that most of the better fans use do not produce 20 watts most of the time, they only produce this for a few hours a day, around solar noon. For the remainder of the day they produce far less power and therefore move less than the rated output.

Problems with electric powered fans:

There are several types of motors. The common roof vent fan motor is a cheap watt hog that uses 325 to 720 watts of power or $18.75 to $41.17 in August. You can buy quite a bit of air conditioning for that amount. If you do use an electric fan specify a "Quiet Cool" brand fan (Amazon) which uses 108 watts of power.

Problem with ALL fans:

In theory the fans draw air from all vents in the attic equally. In actuality the movement of air has friction, meaning all powered vents draw mainly from the closest air source, another roof vent. This means powered vents are effectively useless.

Why people swear by fans:

People want to feel good about the $900.00 that they spent on a fan.

People equate fans to cool.

Some falsely believe that fans are required to stop mildew growth, this is not true

Ok I am convinced WHAT SHOULD I DO?

Install more unpowered vents. It's not sexy, not expensive, but effective. That's what I did on my second home. I did it myself and boosted the free air movement by 60% for less than $80.00

The Villages only installs the minimum number of vents as required by code.

[wisbad1]

We have the solar attic fan installed by the solar guys. We had it installed in the storage area directly above the stairs. It certainly drops the temperature in the attic and is easy to see if it’s running. I just press the button to lower the stairs. I can see and hear it running from ground level.
What kind of electric stairway do you have?

[Toymeister]

If I had a roof exhaust fan installed, I would want to know how I can check to verify that the fan is actually functioning and moving air. Some people think they have a functioning fan, but it has been broken for years.

Whole home energy monitor is what I use. Home - Sense.com (http://www.sense.com)

[Toymeister]

We have the solar attic fan installed by the solar guys. We had it installed in the storage area directly above the stairs. It certainly drops the temperature in the attic and is easy to see if it’s running. I just press the button to lower the stairs. I can see and hear it running from ground level.

It's funny, I have stairs where I press a button to open and I feel a great deal of air moving into the attic when I open it as well. I have two static vents near the stairs opening. So look as me as a control group. As I don't have fan powered vents.

The movement of air because of the stairs opening is not a measure of ventilation, it's the physics of thermal dynamics (temp differential).

But I do understand that it's easy to credit the fan for this. I believe the improvement is because there is an extra vent to the roof peak, not because it is powered by the sun.

[Kenswing]

What kind of electric stairway do you have?
https://majicstairsinc.com/