Remodelers don’t often think about energy efficiency and building performance for K&B remodeling. But paying attention to a few key issues when planning and renovating kitchens and baths can pay big dividends for you and your clients.
The 800-pound gorilla in the kitchen is the rangehood. Upscale kitchens — often with six- or eight-burner ranges with rangehoods that vent as much as 1,200 cfm of air out of the kitchen — are far more than the average homeowner needs, unless they’re frying turkeys or cooking for a hundred guests.
These monster hoods pull the equivalent of about 3 tons of HVAC out of the house — moving air that your customer paid to heat or cool straight to the outside. Not only is this inefficient, but when a big rangehood is installed in a properly air-sealed house, there’s potential for backdraft from water heaters, furnaces, and fireplaces that are not sealed combustion or are not properly isolated from the interior. When appliances backdraft, you run the risk of carbon monoxide poisoning, which can sicken or kill people — not good for business.
The best way to avoid these problems is to put in a smaller rangehood. If you can’t convince your client to do this, consider having an experienced HVAC contractor install a make-up air system similar to those used in restaurants. Though this type of system can be complicated and inefficient, it will prevent a lot of problems.
Another key issue in kitchens is recessed lights, which, if installed in an insulated ceiling, can let air leak in and out, reducing efficiency and comfort.
Time to Vent
Bathroom vents tend to have the opposite problem of kitchens vents — they don’t exhaust enough air. Spring for Energy Star products, which work better and are quieter. Duct them to the outside (not into the attic!) using the most direct route and with as few elbows as possible. Install a timer, delay switch, or humidity sensor, so the fans run for 20 to 30 minutes after every shower to make sure they remove all that moisture, helping cut down on mold and mildew.
Install an air barrier of drywall or spray foam insulation on exterior bathroom walls before the tub is installed to eliminate air movement and to keep the tub comfortable in cold weather. Avoid using vinyl shower curtains. You can build the most pristine, VOC-free bathroom in the world, but that vinyl shower curtain is about as toxic a material as you can put in a house.
There’s a lot more to consider in creating green kitchens and baths, but properly addressing ventilation and air sealing is a good place to start.