Beware Salespeople's Estimates Sizing HVAC and other Housing Features

This homeowner's furnace trouble reminds us of 2 important principles.

Sasknelli at LittleHouses wrote about her furnance-buying experience:

These guys were very condescending. I was shocked to discover that some of these salesmen didn't even know the difference between 2speed and 2 stage and yet they talk down to you as if you know nothing. I did finally find a knowledgeable salesperson who was willing to listen. I got close to what I wanted and the price was around 40% less than what the other contractors were pushing. Anyway,when it was finally installed and the gas inspector came, he told me he was very impressed with the furnace I had chosen. He said that in his 22 years of inspections in the Province of Saskatchewan, mine was only the 2nd house that had the correct size furnace in it. That's pretty awful to contemplate.

Remember:

• Design Smartly: Build in ways so you need as little ongoing energy input as possible. Passive designs (as mentioned here on this site) keep your wallet full. With well-designed initial infrastructure or a super-insulated building envelope, at least you only pay once at the start, you do not pay continuously for the extra fuel and electricity to overpower a bad home design.
• Know Your Design (Know Your Needs): There is some wisdom in buying some extra capacity as insurance but beware the saleperson's old tactic of trying to get you to "upsize"--it happens with homes and furnaces and solar-power systems just as surely as it happens with the McDonald's request to supersize your French fries. Many salepeople try to maneuver buyers into the highest profit margin (for the seller, or the sales commission) rather than into the best product for the buyer's circumstance. If malice is not the problem, ignorance might be: Many salespeople get trained in a myopic cookie-cutter way and would not know how to size your system accurately even if they wanted to do so (particulary when integrating a furnace choice into all the other variables including thermostat, insulation, landscaping effects, etc.).

Another lesson on mistakes to avoid: Live Better by Spending Less: Avoid this Unlivable Luxury Home