By Garlynn Woodsong | Chair, CNA LUTC
I’m a planner who specializes in the impacts of urban development on greenhouse gas emissions. As a realtor and a general contractor, I spend a lot of time on job sites talking to people in the trades, in offices with professionals hearing about the latest technology, then installing it or otherwise having the opportunity to observe it in action.
I’m very interested in technologies that allow us to fuel-switch away from carbon-based fuels and toward electricity and other options to achieve net-zero-emission lifestyles. Installing solar panels on a house — ideally a minimum of three kilowatt-hours capacity per roof — provides power for water, home heating and home cooling services to shift efficiently toward electricity.
In this context, I share with you three strategies to support fuel switch to electric in pursuit of net zero, with which I have some experience:
There are two basic types:
- A standard insulated-door fan sits at the top of the livable space. When turned on, the insulated door on top opens to allow the fan to blow the hot air from the house interior into the attic, where it escapes through roof venting. You may have to add more roof vents to provide sufficient square footage for quick, efficient ventilation.
- An in-line fan can either hook up to your existing HVAC ducting system, or be installed as a new duct run, to suck hot air out of the house.
Both use much less energy than air conditioning systems, but during much of the year can be just as effective at cooling your house.
The downside is they cool the house by sucking in outside air through open windows in your house. Thus, if operated when outside air is not noticeably cooler than interior air at the top of the house, they won’t make much difference.
At all other times, however, they really work well, especially at providing moderate-weather cooling.
These come in two varieties:
- Ductless mini-split systems are the most common. An interior “head” unit – a rounded rectangle about 18 by 36 inches that sits high up on the wall – is connected via heating/cooling pipes and an electrical cable to an external unit, just like built-in whole-house air conditioners. It also features a condensate drain tube, which can either be routed to a drain internal to the house – like a floor or laundry drain – or to the outside of the house through a wall.
- Ducted mini-split systems use ductwork to distribute their climate control services to each room.
Hybrid heat pump water heaters
These are the latest and greatest in water heating. Five years ago, it was tankless water heaters, but these units are now available for one-half to one-third the price. They operate by using a heat exchanger to suck heat out of the ambient air, and use it to bring the tank of water up to room temperature.
The electrical heating element is then used only to elevate the water from room temperature to the desired setting. They are more efficient at heating water than anything except passive solar panels. However, they have two issues:
- They can be loud. Not just a little loud, but jet-plane-taking-off loud.
- Did I mention they suck heat out of a room? Yeah. They need at least 100 square feet of room to operate, and more is better. They will keep a room that size cool like a wine cellar, by transferring room heat into the water. They should be placed accordingly away from sleeping areas and in open areas with lots of cubic feet of air is available from which to suck heat. Garages, attics, basements and large utility rooms are thus the best places to put them.
All three of these are technologies that will save you money on home operational costs. Each home and each system would have its own cost-benefit ratio and, if you’re curious, look into each one further.
Although this sort of home energy efficiency upgrade discussion is a bit beyond our usual discussions, the CNA Land Use and Transportation Committee meets the third Wednesday of each month from 7 to 9 p.m. in McMenamins Kennedy School Community Room. I encourage you to join us Sept. 19 for a discussion of current land use & transportation issues in our community.
Garlynn Woodsong lives on 29th Avenue, serves on the CNA Board and is an avid bicyclist. He also is a dad who is passionate about the city his son will inherit. He is the planning + development partner with Cascadia Partners LLC, a local urban planning firm. Contact him at LandUse@ ConcordiaPDX.org.