I'm having three HVAC contractors come to my house tomorrow to give me estimates for replacing my gas furnace. What should I look for to identify a quot;quot;reputablequot;quot; contractor, and what questions should I ask?Just for clarification, I'm replacing a 15-year old gas furnace that has a cracked heat exchanger. I'm probably going to get a two-stage, variable-speed-fan furnace. What questions should I ask the contractors, and what information should they be gathering from me? I know that they're supposed to do a quot;quot;heat loss calculationquot;quot; but I have no idea exactly what that is or how it's done. Any advice from mefites that have gone down this road (or are HVAC contractors) would be appreciated. Thanks!
Heat loss calc? Hmmm. I doubt you need this. They size the furnace based on square footage mainly. Do you have big heat losses that need correcting? A good contractor can help out here too and when you are putting in a new furnace this help is essentially gratis. You want to know what furnace, how efficient, how big, how much money, schedule, and some contacts of prior satisfied customers. Do you have other issues, such as cold rooms, hot rooms, etc.? Ask about those and how they propose to solve them. Who is getting the permit (it's easier if they take care of it)? After price, the biggest issue with any contractor is quality and schedule. Ask around and see what kind of reputation the contractor has on these issues. Sometimes you just have to go with your gut after interviewing them.
To help identify a reputable contractor, get some references and call them.
The most important question is the percentage of efficiency of the furnace that you purchase. Make sure that you decide what you want first and that they all bid the same ....no actually have them provide options for the different efficiencies available which may be different by code in your area. You may be limited by being able to get out with a stack. depending on the efficiency you may need to get a vent outside so this will play a role in it as well. As for the calculations it is not really something you need to be too concerned about other than to know it is their responsibility to do the calculations. It has to do with the percentage of glass vs. walls and what insulation values are in the your home walls, attic etc. This may be a good time to go ahead and upgrade your insulation if it is needed and it may save you money on the furnace. Also check and ask about rebates from the electric companies and gas companies for doing upgrades on your insulations and efficiencies there is probably some money out there for you and it is not just peanuts it is often considerable so makes sure to ask the contractors AND call around to your local goverment and utility companies and find out about assistance available I would be willing to bet there is some money out there for you.
most wont do a heat load calculation. your duct work is sized for the current unit. going bigger or smaller will only hurt efficiency. when you ask them why they chose that size, they are going to say its the same size as the one you had. the heat load is calculated by the engineer that designs the system for the house. some HVAC outfits offer efficiency audits, if you are interested in such services. look for a mechanical permit number on his truck. usually on the front fenders or the doors. ask them to show you the crack ( or demonstrate it, depending on where it is.) usually its on the bottom of the heat exchanger. dont let him rush you out of the way. make sure you see it too. 2 stage is a good idea as long as your old unit didnt run all the time. if it did, chances are the new one will too, which means it would never kick down to the more efficient speed. your old unit was most likely a 80% AFUE (efficiency) there are new units up to 95% efficiency, but they require some rework. if you go that route, make sure the work is noted in the bid. make sure all code updates are included in the bid. ask how long they have been in business. estimates are free. leave the business cards out on the counter for the other bidding contractors to see. they will know they are competing with other contractors and they wont try to club you like a baby seal with a 5000 dollar bid.
