Poor insulation is usually the culprit although if you enter the attic on sunny winter day your attic space can be warmed by the sun more than your furnace.
My attic is extremely hot.
If the joints in your ductwork are not properly sealed your forced air system can suck attic air into the ducts air that s either really hot in the summer or really cold in the winter.
Another reason your attic is so hot is because of insulation.
Hang an outdoor thermometer in your attic making sure its range.
Frustratingly for those who find themselves in this position both of these problems are totally avoidable.
An unventilated attic can reach 150 degrees in the heat of summer 50 degrees higher than it should be.
With enough exhaust vents and intake vents your attic has breathing room and is better cooled.
An overheated attic can bake asphalt shingles on the roof and cause them to deteriorate.
The best is soffit vents all around and a power ventilator close to the ridge pole.
The result is an extremely hot attic.
Unless your roofing system has insulation on the roofing deck and is designed without ventilation your furnace should not be heating your attic.
Take its temperature.
If the ducts aren t insulated the ductwork will be at the same temperature as the attic warming your cool air supply during the summer and cooling your heated air in the winter.
Excessive heat deteriorates items you store in the attic and can cause moisture problems in your house.
Common complaints when loft conversions go wrong are that they are unbearably hot in the summer and extremely cold in the winter.
There is no reason why a relatively new loft conversion should not be thermally.
Even after the sun goes down the hot items in the attic will continue to radiate and conduct heat keeping the air inside warm long after the outside temperature has cooled down.
Not the overabundance but the lack of insulation in the attic.
On a hot day when it is for example 90 degrees fahrenheit outside but 130 degrees fahrenheit in the attic when i turn that fan on the entire attic cools down to say 100 degrees fahrenheit in like 15 or 20 minutes.
You can t have too much ventilation.
Not ideal of course.
The sun s radiant heat is the engine for all this and the process continues as long as the sun is shining on the structure.
There is near zero benefit for venting the attic other than the above mentioned roof.
Add a power roof vent fan and that has a thermostat on it and it will come on when the attic gets hot.
And it can cause your air conditioner to work harder than it needs to and send your energy bills soaring with the temperature.