get a 2nd quote from another company. do you feel ok writing a check for $12k based on 1 estimate?

Get some more quotes to confirm the price is competitive. Get the XR15 or another brands highest efficiency single stage. I would want higher than just 13 seer.

Ask for a heatpump instead of regular A/C. Price shouldn't be much more. This would allow you to heat cheaper than the oil when the weather isn't too cold and the price of oil is high. Heat pump heat is fine when weather is above 30 degrees unless the house is drafty.

You should get at least 3 quotes. You should focus on how each contractor proposes doing the installation. From this you will learn the strengths and weaknesses of each company.

I think the summers in CT are humid, so my recommendation would be to get a 2-stage condenser with a variable speed air handler. The heat pump may be a good option considering what your are paying for fuel oil.

Geek

You need more quotes.

I would want at a minimum one return upstairs and one return downstairs, properly sized of course.

I will assume you don't have nat gas access.

Add a HP instead of straight AC. This will help you in the shoulder mths and when temp is at or above temp balance point. Even at that, you could stretch the use of the heat pump with a heat strip that would be cheaper from an operational cost standpoint than the more expensive fuel oil.

Post electric rate and cost of fuel oil/gal.

IMO

"I am not convinced the guy did a model J calculation."

I'd just add that some companies get 95% of the Manual-J done by pulling plans @ the county office. When they show up on site they'll add the glass and door R-values. I ended up doing a full Manual-J myself because I thought they were B.S.ing me r.e. this method. All the heat gain and loss numbers were within a +/-2k range of my calculations.

You should absolutely get some more quotes from reputable HVAC contractors. I was very pleased with the A-rated Angie's List folks I had in my home.

(10) 6" supply ducts will not produce the required airlow (1600 cfm) for a 4 ton system.

Find a company that will supply you with a Manual J calculation.

Here is a link that might be useful: 9 facts you should know before investing your money in a central system

Ed is right, there is no way that is going to work as far as air flow is concerned. The system you should be looking at is a ductless A/C system. In this case you may need to do 2 single head systems to account for the higher heat load, but someone who does a proper manual J (which must include a blower door test to measure infiltration!) will be able to tell. As a company, we rarely install ducted systems anymore, they are a very low value and have much higher maintenance costs and lower efficiency. With ductless you will not need to install any ducting and will get near geothermal efficiency. PLUS it will cost almost 1/2 of your horrible, horrible first quote.

Here is a link that might be useful: Ductless Info and Pictures, etc.

Thanks for the replies everyone. I had some last minute travel for work, so haven't had much time to read what you all have to say, but catching up on it now.

1. Of course Iw ill get multiple quotes, I wouldn't spend 1K without getting multiple quotes let alone 10-20K.

2. Not interested in a heat pump. Electric rates are high here. House is fairly efficient, and I have a nice wood stove insert and 5 cords of wood read to go. Keeping warm is not my problem.

3. Correct, no natural gas available here. If it was, I would probably switch over.

4. Thanks for the information that 10-6" ducts will not supply enough air flow for a 4 ton system. Thats the sort of info I am looking for!

5. Started reading about mini-splits for use in the entire house, I think thats what you mean barrongreenteam...? Are they variable speed? Because I dont seem to see one under 9K BTUs, which is too big for the bedrooms?

Ive found this too. A lot of the HVAC folks will do things by the seat oftheir pants without rigor, not give you any real basis for what is being charged, and then act like how dare you question it...

More quotes is a good thing. Nothing wrong with a slightly lower unit in terms of tonnage, but if you know the unit you want for tech/efficiency.other reasons, no reason you shouldnt demand it. The installer may advise against it based upon experience, and that's good valuable info... But you need to decide what you really want.

Air flow of 10 pc of 6" supply will most likly only diliver under 2.5 tons of cooling and huge static pressure issues.
I would only install 7" flex ducts . and damper down only if needed.
his design 10 6" supplys at 1600 cfm will be noisey ,long run times and very high static pressure beyond mfg specs.