questions regarding purchasing AC/heater unit for home

Pawl

I have forced heating only. I want to get an a/c - heater unit installed in my attic. 1950 sq ft - 2 story built in 1965. I lived in southern calif with hardly any humidity. I want to do my homework before I start getting estimates. Original heater is built by Carrier in 1975. It says input is 100,000 btu /hr and bonnet capacity is 80,000 btu /hr. Maybe I can get some pointers on what to do 1st to get started and keep posting here as I walk through the process. I have metal ducts but I obviously dont know if they will be the right size for the next unit. Any input would be appreciated. I have dual pane windows,lots of insulation in attic,carpet,composition roof,3 turbine vents on roof,all ridges have 1" gaps at top and that gap is covered with honeycomb type plastic piggyback roofing vent caps that allow heat to rise out of attic,stucco,raised foundation,3' eaves all the way around both stories. House faces the west. Any thoughts?

joecaption

#1 Get rid of the tubine vents. All you need is the ridge vents. The ridge vents are doing nothing but sucking air in through the turbines instead of through the soffits.
What your looking for is called a heat pump.

TarheelTerp

Is this existing unit in the attic?
What sort of fuel does it use? Natural gas?

Pawl

My existing natural gas heating unit is in the 30w x 35d 1st floor hallway closet. All my neighbors had their new unit placed in the attic.

I understand what you mean by the turbine vents bumping heads with what the ridge vents are trying to do. I researched online the turbine vents and ridge vents together and did not realize all the pros and cons of having them together. I installed ridge vents with a new 30 year roof back in 1993 and 20 years later it looks really good. Theres no hurry to change it back now. I want to do some testing with outside and inside temperatures this summer here in southern calif. My house was built in 1965. The soffets measure approximately 14"x3" and are all wide open with plenty of insulation over the ceilings.

My house is nice in the summer time with a swamp cooler. Yes a swamp cooler only because I could not afford an ac system being a single parent back then but today I have the money. I actually am impressed with the swamp cooler considering it is just an electric bench grinder motor doing all the work. Very inexpensive to run but a pain in the butt to keep the temperature balanced in the house. Anyway, enuff said....

TarheelTerp

So you want to do the same thing?
Is your existing duct work oriented around that closet install?

Maybe you don't understand.
The ridge vent is the one that stays... the turbines go.

Have you had the power company LINK or a qualified HVAC pro LINK give you any objective information LINK to help this process?

Not even close. Follow up on those links.

sammy37

Ever paid a power bill in California? Trust me, the OP wouldnt want a heat pump, natural gas is the only way to go out there.

sammy37

The biggest problem with keeping the furnace in the closet, is the air return underneath is undersized and noisy. If there was room to add another return off the side of the furnace in the closet and branch it to somewhere else that would be fine but most of the time there isnt.
I remember most of the old Southern Cal homes were set up like this and not to mention, a new furnace with inshot burners and larger noisier blower will be annoying to listen to, especially if the furnace closet is near the bedrooms.

TarheelTerp

This is true of 99% of remodel & update jobs

There ya go.

Pawl

The furnace closet is on the single story side of my house. The upstairs has two bedrooms and one bath but these rooms are over the kitchen, living room,dining room. I am guessing the new unit will need to be mounted in the open area right above the furnace closet where old unit is now to be the farthest distance from the bedrooms in all directions. The upstairs bedroom closest to furnace closet has a small door leading into 1st floor attic so accessing open area above furnace closet is easier. The distance from this bedroom to open area above closet is about 10'.

I don't think I can figure out ducting layout until I get the load calculations down. I am going to check out the $49 load calculation program online. If I can go that route then that will be my next move. I believe I have to get that done 1st before another step.

I also wanted to run rigid ducting because I figure if I install it then the cost of it will be justified. I worry about soft flex getting crushed etc,....