5 furnace estimates and more confused than ever!


Old 09-22-05, 08:06 AM
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5 furnace estimates and more confused than ever!

Greetings all;

I live in Milwaukee, WI and am upgrading a furnace in a house I recently purchased. the house was built in the late 1950's, standard stick frame w/ basement. The house is about 1050 sq. ft, single story ranch, 3 bedroom. I have received 5 (count them - 5!!) estimates and they are all pretty different. anywhere from 50k btu to 75k btu; 80% efficiency to 96%; two stage or 'standard' (my word for a non-two-stage, not theirs). Heat is natural gas. I tend to be energy/environmentally aware and would prefer a higher efficiency, but one guy told my that a high efficiency (>90%) would be a waste of money now and $$ and energy during operation; he says the house is too old and isn't built for high efficiency; he says a 85% efficiency 75k btu, two stage (40-30) would save me more money now and later. The other extreme is a 65k btu 96% efficiency. there's a 50k btu recommendation in there too!

I will also be installing an air conditioner - there is none now and am aware of the duct size upgrade. my lateral ducts are 4" not the needed (?) 6"

Help - please!. I try to be an informed consumer but am totally lost here.

Also - any thoughts on installing radiant floor heat or pellet stove in place of or in addition to furnace would be appreciated.

thanks so much in advance
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Old 09-22-05, 07:01 PM
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Five bids

The first question you should ask each of the bidders is: "Did you do a Manual J ?" If they look at you like you have three heads, say "no", or give you some song & dance about they have done several houses like yours, etc., tell them to take a hike. Here is a link to a site where for about $50 you can download & run a Manual J (heating & cooling load calculation) for yourself. http://www.hvaccomputer.com
Duct design is a whole 'nother story. The calculation for this is done using a Manual D. The previously mentioned program incorporates something of a Manual D, if I recall correctly. Once you get the loads, you will be far better able to compare quotes & operating costs.
Old 09-22-05, 08:54 PM
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I agree with Grady 100% on the program..

most important thing is, are you going to update the windows? Attic insualtion. Cuz if you sized the system for your home now (If nothing been updated) you will have an over sized furance.

With gas price going though the roof this winter, you better have a system that is sized for YOUR home. You'll get the best out of the system.

As for the "85%" there is NO such thing as a 85%..... They go up to 80%, that's it.. With gas price going up, What would you want to do get something that will save you money on a 90+% system?

A 90% system has a less chance for you have drafty windows since it's a sealed system. where, the 80% is not sealed. so it will take your air that's already heated up the the chiminey, the air lost will the pull the cold WI winter air into your home, and you'll have to reheat it.

If you want to save on power, go with the 90% system with variable speed blower.

A regular blower on an avg takes about 700 to 800 watts of power to run.

A variable speed blower takes up to 100 watts of power to run. most of all, it's quiet!
Old 09-26-05, 07:10 PM
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5 estimates . . . thanks for replies

Thanks for your replies Grady and Jay11J. I asked all of the contractors about a manual J and they all replied "I've been doing this so long . . . . .". Those who offered would charge me $300! I've seen the website for the computer version for $50 but have heard it is next to impossible for a homeowner to find/acquire the necessary info. I've decided to opt for an energy audit and heat load analysis - basically a manual J with add-ons. I'm hiring an independent enegry consultant who doesn't sell furnaces. I figure it will run me about 5% of the cost of the new system - hopefully a wise investment.

thanks again

Old 09-26-05, 08:17 PM
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I used the program on my parent's new home, and It wasn't that bad.. Just give yourself a few min at first to figure everything out.. Once you got it, it's cake walk to do.

So it's up to you if you want to spend the $50 on the hvac program that Grady link you to, or hire someone to do it..

Keep us postedon what you find.
Old 09-26-05, 08:32 PM
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You do want to think also about how long will you stay in the home here. If 10 years go for the good stuff so you get a return. That far north go for a AFUE of 90% to 96% on the heat and the AC go for just a seer of 12.

he says the house is too old and isn't built for high efficiency;
Boy I dont know how he thinks.
No mater what the home is like or the heat loss. The better the efficiency the less it will cost you to heat.

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