Whole House A/C Experts

[Sled Puller]

Here is the scoop:

I have half my place heated with hot water in the slab, the other half with baseboard.



What is the cheapest, most efficient way to cool the whole place?



Thanks,

Gene

 

[fest3er]

Install a heat pump and bury the outside lines at least 8' in the ground. I suppose it might take 10 square feet to adequately spread out the condensor lines. You're guaranteed to have good heat transfer year round. This also means installing air handling inside the house. Depending on the type of house, this can be easy or difficult.



That is about as efficient as you can get, though it may cost more.



Fest3er

 

[redramnc]

If you don't have ductwork already installed it will run up the price more. If you keep the existing heating sources you can go with a package AC-only unit (fan, condenser, and evaporator in one housing) planted outside.



Other way is to go with a split unit heat pump or AC-only. It really depends on the layout of the house and where ductwork can conveniently be installed.



Package unit gas packs run 1500-2000 for 1. 5- or 2-ton unit (I just looked at replacing mine but patched it up for another year). Ductwork cost depends on layout of house.



Free estimates (are they really free?) will give you a ballpark.



Using the ground for heat transfer is a good idea if you have the room to do so. It costs more and alot of HVAC guys haven't gotten into it yet (at least in my area).

 

[Skydiver]

Geothermal

In 1996 I built a 2250 sq. ft. house 1750 sq. ft being heated and cooled. I came very close to having a geothermal unit installed. In 1996 the cost from the only 2 bids were $10800 and the other over $12000.

I wound up with a 3 ton 12seer rated condensing unit that came from a mobile home. After talking with the people in my town that used geo units I learned that the pumps that circulated the liquid solution through the coils underground were troublesum and prone to failure. So I just used the 3 ton unit and could not be happier. I had extra insulation installed in the attic and even went around in the attic with a can of the "foam-a-fill Great stuff"insulation and plugged any holes where the wires went down through the walls.

Highest power bill to this date has been $89. Only thing that runs on 220 volts in my home is the a/c. I even have a gas (propane) dryer. To save even more $ I use a programmable thermostat.

Having taken refrigeration in trade school I knew my knowledge would allow me to service the condensing unit.

The geothermal units are sure to be improved over the last 6 years and I like the idea of how they transfer heat. But my total a/c and heating system(mainly the gas heat exchanger and duct work) cost me $2480 with me supplying the condensing unit.

Tim

 

[C Schomer]

I don't know the costs of your gas and elec but gas is half the expense of elec for heating here. Heatpump is better than elec resistance heat but you already have your heat. The biggest problem with boilers is tremendous stack loss, keeping the boiler hot most of the heating season. A stack damper really helps them. A fan/coil unit in the attic, crawlspace or closet(and ductwork) is what usually happens and remote condensing unit. Evap coolers are popular here, with the dry climate - can hardly see an increase in the utility bill! Craig

 

[Todd T]

you could just leave the refrigerator door open



Central air is the way to go Gene, do you have a closet in the middle of the house or is there a basement under the house? you need the forced air unit in the middle of the house usually. with a return air either plumbed into the door of the closet or actual ducts ran to it from each end of the house. do you have any wholesale places around you? you can buy from them, do it yourself kits that have schreader valves on the PRE-Charged, order to length, line sets and the A coil. all you do is install and screw them together. same for the condensor.



when i did my house, i bought a high efficiency furnace for each floor and then put the A coil in the ready made plenum and ran ducts to each room. for my first floor the unit is in the basement and the ducts come up to each room from below with the returns in three of the rooms. for the second floor the unit is in the atic and the ducts come to each room for the ceiling with the return in the ceiling right under the unit. air coming from above is the best for the cooling cycle as cool air sinks. you can buy upright and horizontal air handlers too. but they cost about the same as a nice furnace and you can get them Vert. of Horz. too. even if you dont use it for the heat you will always have that option. and generally the parts are cheaper to repair them.



BTW we heat with a wood burning furnace that is in the basement and is tied into the ductwork of the lower level. the second floor is handled by the small furnace (50K BTU) in the atic.



i never use more than 500 gallons of LP a year. and my neighbor with a exact same house and floor plan as i uses 1000 to 1200 Gals just to heat with and another 500 or so for the rest of the year. but he doesnt have to cut and split 2 cords of wood each summer. so who's the dummy now?



if you go Goe you need 1 ton of capacity for every 1 1/2 tons of conventional. and a 12ft diameter ground loop for each ton of cooling. its VERY expensive where i live but well worth the money form what i hear. i just didnt have 10K to drop for Air conditioning when i did mine.

 

[Sled Puller]

Prolly go with something like that Todd, as I have a large closet smack in the middle of the second floor.

I built my boiler system, so I reckon I can handle an A/C unit after I study it some.



Coming out the ceilings would be smartest, eh?



I have seen some units on the roof out west, I wonder if that is smart in the North east?

 

[Todd T]

yep you heat from below an cool from above. with your setup you have radiant heat in the floors soooo. .



something else to think about now that i know you have a two story. ZONE IT. dont put one system to cool the whole house. our house is like two different worlds. plus we are not upstairs until bedtime. so why cool the upstairs all day and evening when you are not up there?



we have two of those programable thermostats one for upstairs and one for the first floor. they both just do their thing and transition about a half hour apart. that way when we wake up the heat is on downstairs and goes off upstairs shortly after. get the idea? there is a weekly program with 4 settings and a weekend one with 2 settings on each of them. the condensor for the upstairs unit is on the roof of the Garage to help it not have to push all the way up there. its well hidden from the sun and street and it only Keeps the Inlaws awake at night (its outside the spare room they use when they come into town)



we love it!!

 

[Rotty]

Move to the islands, (hawaii, fiji, carribean). With a average temp 0f 75-80 degrees you will not need heating or cooling. Thus you save on electric/gas bill.

I know, smarta$$. But I could not resist. It is friday afternoon here at work and it is almost time to go home... . Oo.