Air Conditioning - AC in an old brick home with Radiant Heat

What would be the best method to put AC in a brick home built in 1870 with radiant heat? The house is 2 stories, 3400 square feet, and located in central Iowa. The attic is 2200 square feet with blown in insulation (last fall). There are not any whole house or attic fans (would either of these also be a good idea?). The house also has a full basement. The boiler for the house is 2 years old, so replacing that is not an option, it was replaced 3 months before we bought the house.


What type of cost should I expect for this? I am currently talking to my local contractor and I just wanted to have an idea of what I should be looking for. I have read some threads on this site with people recommending 2 separate systems. Any information you can give me would be greatly appreciated. Thanks in advance.

You will be far ahead of the game if you put in a separate system for each floor. Comfort will be enhanced, if one goes down you can still seek refuge in the part of the house which still has A/C, & operating costs are cheaper. As for installation costs, two systems will probably be more than one.

2 units for sure here . One in the attic with insulated duct work. One in the basement for the lower floor. With and out let or two down there just to help dry things out. Make sure they run a AC load on the home there and get 3 bids for the job.
Now how long do you run the AC there and how long you will stay in the home. tells you what kind of SEER you should get . Low at a 12 seer and high at a 19 seer.

ED ;)

I will look into those things. I am hoping to have some contractors come out this week to take a look and get estimates. We are planning to be in the house a long time. In Iowa, it is hot from the middle of May to middle of September on average. Very humid at times also. Any guesses on cost, I know that is very difficult but I need to do some figuring. What about the attic fan? Would that also help? Thanks again, this has helped me feel and hopefully seem a little more informed, what a great site!

An attic fan on a tstat is well worth it. make sure you have lots of vents in there for the attic. 1sq ft for every 150 sq ft of attic. 1/2 in 1/2 out. Attic vent fan, attic sq ft X 0.7=CFM of fan.

ED ;)

This is a post from a similar situation.

My idea on your situation is this. It probably is more important to find a qualified dealer experienced in adding AC to an older 2 story home than the selection of the equipment itself. He must have experience with adding ductwork and the best method for accomplishing this both in reasonable cost,aesthetics, and your ultimate comfort. Ask around for dealer recommendations from your friends/neighbors who have similar type homes. I assume you will be keeping your radiant heat for the heating season. I agree with Grady that two separate systems are the preferred method. Just a thought but you may want to consider purchasing heat pumps and use your radiant heat only on the coldest days of the winter.This might depend on how well your home is insulated and the cost of energy(may or may not be cost effective). I would definitely insist on a written heat/cool load calculation for sizing equipment on each floor. Purchase the highest SEER you can afford-say a minimum 13-14 SEER-and variable speed is a nice feature but more expensive. Difficult to say about costs-depends on labor rates in your area, size and brand of equipment selected. This is not a project for an inexperienced dealer! Get some references and go see the dealers' work. Good Luck!

http://www.warmair.net/html/fuel_cost_comparisons.htm

you might be interested in a high air volume style unit. They are bit more expensive but do a great job on retrofitting and go in quickly. They also do a great job of dehydrating the air as the coil is about 6" deep and the regitars are less intrusive, they have about a 3" round opening, and can also use wood dressing rings, or the typical white alibastar. The ducts can be snaked between walls cavities where required too!