bhebert

tell us about your home.

what area of country do you live?

what is your electric rate?

generally, I think with today's high energy cost an 80% AFUE eff nat gas furnace is a dinosaur unless there are installation impediments with high eff models.

and I am not a fan of the two stg condensers unless you have a special application like zoning or the cost diff is relatively close with applied rebates.

I would want a furnace with a var speed blower and a stat that has "dehumidify on demand" feature if you live in a summer climate with high humidity.

IMO

bhebert...First let me state that I am not in the hvac field nor do I have alot of working knowledge about it, however just 2 months ago I put in two new complete heat pump systems, and based on that I think your "best" proposal is too high. The reason I say that is this... below is a description of the systems installed in my home,

5 ton heat pump: 2 stage copeland scroll compressor / variable speed / 18 seer / included tearing out old ductboard plenum and replacing with sheet metal plenum, / matching air handler & coil / new honeywell vision pro touch screen programmable thermostat and new concrete slab for outdoor condensor unit.

also:

2 ton heat pump : exact same criteria that I listed for the 5 ton heat pump, plus replacing old flex duct with new sheet metal duct that supplys air to out den.

My units are manufactured by AIR EASE. AIR EASE is a division of the Lennox Corporation.. and the warranty for both my units is exceptional, 10 years across the board, 10 years on the compressor, 10 years on parts ( thats 5 years longer than your best proposal on parts ) and 10 years on labor. ( thats an additional 9 year warranty than your "best" proposal. And while the name plate on my units say "AIR EASE", remember they are made by Lennox. In fact the parts are supposed to be interchangeable. the price for both units, total cost to me was 18,000. That's alittle more than 5500 dollars more than your quote, but remember it's 2 complete systems with a better warranty. Just to be fair, I also got quotes on Lennox heat pumps, the price for both systems was 19,280. A little more expensive than what I bought, but the seer rating was less and the warranty wasn't as good. When I expressed some concern that I had not heard of Air Ease, the contractor gave me some references of people he had installed these units at.. exclusive neighborhoods, half a million dollar homes. I called several of them and they all said they loved the system and had no problems. Hope this helps. Good luck with your decision

Roland

"enlarge and replace return air grille in hall."

I hope, with a 5 ton system, you have more than one return.

Price doesn't sound unreasonable for equipment quoted (top end) and new ductwork system. Hopefully they size the ductwork properly or neither system will provide its rated capacity or efficiecny.

5 tons is a lot of cooling. Did they do a load calculation to size equipment? I'm guessing you live in a warm climate, since most 5 ton systems require more than 72k btu heat (90k x .80).

tigerdunes,

i live in southeast texas near houston. i am pretty sure he did a load calc as he took measurements of the house and noted the number of windows, insulation, etc. i am going to ask him specifically if he completed one though.

regarding the furnace, i am wondering if i was limited on which model due to the size of the opening to my attic. they will have to remove the hidden staircase just to get the equipment up there. this model is a variable speed though. the furnace quoted is also 2 stage where it will run on a lower setting if conditions are milder. what does the 80% afue refer to? is this the efficiency of the gas furnace? we probably use heat for 2 months of the year down here and i am more concerned with the efficiency of the a/c.

i was told that the 2 stage condenser made the unit more efficient as it will run on the low stage when conditions are milder, saving on electricity.

I feel confident about the duct work being sized properly as i spent some time with him as he examined my current layout. not sure about the number of returns. he did mention that they may add an additional return in the ceiling if the hallway return wasn't adequate. how do you determine the amount and surface area of return necessary?

Bhebert,

- His measurements are a good sign that he's doing a thorough job. You do want to check about a load calculation because properly-sized equipment is the best way to have an efficient system that provides you with optimum comfort. 5 tons may be correct for your hot climate and home.

- The 80% AFUE refers to the efficiency--pretty common to have 80% in your location, so you have the right idea with being more concerned about A/C efficiency, which is your main priority.

- 2 stage condensers do have efficiency and comfort gains, but I agree with Tiger that in many areas similar results can be accomplished with a single-stage system at a lower price. I wouldn't steer you away from it if you are focused on getting the best in terms of efficiency and comfort.

- Glad to hear you're taking the right steps to get the best out of the system. Ductwork is a very important aspect that many overlook. Your system may be a 15 SEER 5 ton, but it may be operating at a lower efficiency and less capacity with inadequate ductwork. The returns are what brings the air back to the unit. The variable-speed blower will increase its speed to get the right airflow, using more electricity and creating more noise, if the ductwork is undersized. I usually like to see more than one return in a home, especially on higher tonnage systems. There are general rules of thumb for square feet of surface area per ton for return air (roughly 1.5-1.75), but it depends on many factors. Ask your contractor about a "Manual D" duct design. "Manual J" is what is used for load calculations.

Hope this helps. Truly is worth it to take the time and do it right the first time for the results in the long run.

ryan,
thanks for the info. i've learned alot on this site and with this being a major investment in my home, i want to do my homework.

this company that quoted me also is a trane dealer. would it be worth it to get them to qoute me using trane equipment?

also, what is your opinion on the whole house filtration system? my wife likes the idea of less dust in the house.

lastly, is the XC21 condenser worth the extra money over the XC16? as far i can tell the only difference is the noise level and the warranty. they are both rated pretty close on SEER rating.

I think it's worthwhile to get a quote on comparable Trane equipment (see if they can quote the XL15i, which is a good single-stage unit, and the XL16i or XL19i). I wouldn't have a problem with either brand.

I assume by filtration system they just mean a media filter system, which is a 4-5" think filter. I do recommend these with new systems as they last longer and have a larger surface area.

XC16 vs. XC21--up to you. You've listed the primary differences. Whether or not the XC21 provides an advantage with that thermostat I do not know since I'm not as well versed with Lennox's product line.

Have you considered a heat pump instead of a furnace and air conditioner? Not sure on your utility rates, but it may be more economical in your climate.