Estimate on new High-Efficiency Heating Solution
I currently have a 85% efficient gas boiler with 5 zones in a house of about 4000 sq. ft. The boiler says an Input of 130 BTU and a Net I=B=R of 108. For water heaters I have two 40-gallon gas water heaters. We do have a Jacuzzi tub in our master bathroom, but it’s rarely used. What is often used is the 5 shower head system [although we try to use only one main shower head for energy savings. Hard to convince the wife sometimes though ;-]
I have a quote for a Lochinvar Knight 119,000 BTU high-efficiency boiler paired with a Lochinvar 68 gallon indirect water heater tank.
The estimate to remove the old equipment, new zones and circulators, venting, condensate pump, drain and labor is $12,500. When I look online I see the Lochinvar parts come in at ~ $5,300.
Two questions:
1) Is that a fair price? I’m not sure what the ratio of parts vs labor should be. It seems high to me, but I don’t want to discount the skill and labor involved to properly setup and tune a new system.
2) How can I make sure they properly size my new boiler. I obviously dont want to buy a bigger unit than needed. Should I make them to do some sort of calculation/worksheet? I think they are basing the new unit based upon the sizing of the existing unit.
Thank you so much for your help.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Frank,
1. It doesn't sound too high to me. Does the quote include new baseboard radiation, or are you getting a hydro-air system (an air handler with a heat-exchange coil)?
2. Ask the contractor to show you his Manual J heat-loss calculation sheet. A Manual J calculation is a code requirement.
3. If you are unsure of the price, get two other bids.
4. Be prepared for some GBA readers to note the irony of your search for high efficiency equipment for your large 5-zone house and the "5 shower head system" in your master bathroom.
The quote does not include to replace the existing air handlers or baseboard heat [we have a mixed system]. All the heat is fed via copper tube to either the baseboard or an air handler.
I will ask for the Manual J calculation. I was looking into it more and my current system of NET MBH is 108. Considering the system is 85% efficient [at best], it gives me a score of 92. That leaves with picking the Lochinvar model that is either rated at 82 NET MBH or 119.
Ahhh! The irony of trying to have an energy efficient house of 4000 square feet, 5 head shower, kids that never turn off lights [hopefully just the CFL ones] and a SUV to carry all our crap around in. I totally understand your point, but a person can TRY!
Frank,
You wrote that you are now replacing a furnace with a boiler. So if you now have a furnace, what are you using to deliver hot water to your hydronic baseboards?
I think I am incorrectly using the terms interchangeably. I thought a furnace and boiler were the same thing. [Just ran downstairs]. What i have today is a water boiler and that's what I'm replacing it with. The new water boiler would support hot water to the air handler as well as baseboard heat via separate zones as it does today.
Sorry for the confusion. I updated my original post for posterity and SEO ;-)
Frank,
Thanks for editing your original question.
A furnace makes hot air that is distributed through ducts.
A boiler makes hot water that is distributed through pipes or tubing.
Just found out the NET of the new unit is 144k. My old unit is 92k. Since I'm investing about $8k in spray foaming my attic I would think that the demand for heat would actually be less. Either way, I asked them to do a Manual J and they had no issues doing that for me. Once again, thanks for the help and guidance.
Making a 4000 sf house more efficient is like getting a titanium bicycle for a race when you are not in shape. It is all we can do, given that what we have is IT. So, do what you can with the behemoth house, 'cause that is what you have. Glad you are trying.