Pros and Cons of Attic Ductwork?
My husband and I are looking into Geothermal. We currently live in a 2350sqft 2 story house built in 1976 that has a forced air oil furnace and A/C. In the summer the upstairs gets much warmer and the downstairs is much cooler and the windows get condensation on them from the temperature differences. (we have old storm windows that we will replace in a few years but the 33 old oil furnace is on it's last legs). FYI: Our system has floor vents and no wall/ceiling returns.
I think it is tolerable, but my husband wants to fix the system by doing a split system (whether we go Geothermal or not). Our attic is probably not up to today's insulation standards so I am sure that would need to be improved and our attic does not have any fan so I am sure that should be added as well.
I am curious as to the pros and cons of installing attic ductwork. I am sure the idea of installing cooling systems in the attic is based on the theory that cold air falls down and it would solve our upstairs heat issues. However I am concerned that even if we install better insulation and an attic fan that our attic is not built to handle such a system and doesn't have the proper sealing and ventilation.
My concerns are that an attic system would mean
- the size of the system would have to be increased to compensate for the inefficiencies of our attic
- The system would have to run longer to make up for the losses in the attic ductwork
- Inefficiencies due to the fact that the cooling system is generating cooling in the hottest part of the house
- Installing ducts will make the attic heat migrate down into the house through the ducts making the system have to run longer to cool the warmer air in the house
- And just the opposite in winter, the house heat will rise up through the ducts into the attic and be lost.
- We have very poor access to the attic (through a small closet) and it woudl be difficult to change filters.
Are my assumptions correct? Is there a better way to solve or problem or because we are doing a retrofit is this our only solution? I assume that installing attic ductwork is going to run us an additional $10k ,plus the cost of additional insulation and a fan.
Also does anyone know if a split system geothermal is more expensive than a self contained unit?