4 Ways to Fix Your Duct System
I've written a lot of articles about ducts here, but I haven't yet addressed today's topic: common problems with ducts and how to fix them. This one is for homeowners or renters who want to save money and be more…
HVAC design
Air Conditioner Sizing: Load Calculations vs Rules of Thumb
It's time to revisit one of my favorite topics: air conditioner sizing. Many contractors use rules of thumb to decide what size cooling equipment to install. Usually, the rule is based on the amount of conditioned floor area, and contractors…
How to Cheat on a Manual J Load Calculation
Sometimes a house just needs a lot more air conditioning than building officials want you to put in, right?* It's better to be safe than sorry, so having extra heating or cooling capacity can be a good thing. Today I'm…
A Heating Load Rule of Thumb That Worked
Sizing a heating or cooling system should start with an assessment of the heating or cooling load. Nowadays, we know the physics behind heat transfer, so we can come up with fairly accurate predictions of how much heating and cooling…
Cool Hand Luke Meets Air Conditioners
Using the wisdom of Cool Hand Luke to explain building enclosures, mechanical systems, or indoor air quality is a long established tradition in building science. Joe Lstiburek's Cool Hand Luke Meets Attics is the pinnacle of this genre, of course,…
Understanding Manual J Occupant Loads
People complicate things. If, say, you want to sell a motorcycle, you place an ad and interested potential buyers come check it out, maybe take it for a little ride, and then one of them buys it. But every once…