My previous post on green homes,Greening an Existing House – Part 1, focused on the issues with building a new house in terms of sustainability, but today in celebration of our purchase of a house in Castlegar, BC; I’ve decided to focus on some of the ways we can make a 10 to 40 to 100 year old house more sustainable. I’m not intending this post to be all-encompassing, just some ideas that came to my head. I’ll follow up with some links next week.

The Easy Greenings

Pick the low hanging fruit, Compact Fluorescent light globes, weather seals, gap insulation, and water saving devices. For little more than 50 to 100 dollars you can save money, energy and water in your household. That was the easy stuff, and although important starting points, may be worthless if other things aren’t changed. Read more after the jump…

Heating and Cooling


These are two of the biggest greenhouse gas costs in your house, whether you live in Alaska or Florida, everyone has the same problem. They want to maintain a comfortable temperature inside the house, and the further away from the ambient temperature we try to make it, the more power we use to do it. Not the most sustainable way of living.


In the middle of summer that generally means, closing the doors and cranking up the air con. I can say from personal experience that 45 degrees Celsius is not pleasant without air conditioning, but in the house we were living, it would have been throwing money at the power companies as the efficiency of the house was so poor. So rather than waste the money, we made do without. An offset to that was that we would drive to the mall to get into some air conditioning. As long as we were going to the shops anyway, or had planned to go on the next hot day, we weren’t adding to our car usage just because it was hot.

So what are some alternatives to air conditioning in an existing house?

  • Shading windows with awnings,
  • In ceiling roof insulation,
  • Roof ventilation,
  • Window and door seals,
  • and paradoxically cross ventilation and ceiling fans.

And you might ask, is air conditioning really that bad? The short answer… Yes

Air Conditioner Tips

Well, if you are going to use an air conditioner, use it sparingly, and take these tips on board…

Electricity Choices — Air Conditioning – Staying cool while saving money

  • Set your thermostat at 25°C or higher. Each half-degree setting below 26°C will increase your energy consumption by approximately 8%.
  • Use bath and kitchen fans sparingly when the air conditioner is operating.
  • Inspect and clean both the indoor and outdoor coils. The indoor coil in your air conditioner acts as a magnet for dust because it is constantly wetted during the cooling season. Dirt build-up on the indoor coil is the single most common cause of poor efficiency. The outdoor coil must also be checked periodically for dirt build-up and cleaned if necessary.
  • Check the refrigerant charge. The circulating fluid in your air conditioner is a special refrigerant gas that is put in when the system is installed. If the system is overcharged or undercharged with refrigerant, it will not work properly. You may need a service contractor to check the fluid and adjust it appropriately.
  • Reduce the cooling load by using cost-effective conservation measures, such as shading east and west windows. When possible, delay heat-generating activities, such as dish washing, until the evening on hot days.
  • Over most of the cooling season, keep the house closed tight during the day. Don’t let in unwanted heat and humidity. If practical, ventilate at night either naturally (e.g., by creating cross ventilation with open windows) or with fans.
  • Try not to use a dehumidifier at the same time your air conditioner is operating. The dehumidifier will increase the cooling load and force the air conditioner to work harder.

And my tip, don’t use other appliances that generate heat at the same time, lights, toasters, ovens, kettles, etc… In a closed system, the air conditioners works heaps harder just to maintain a temperature when there are heat sources in operation.


In the middle of winter here in Castlegar, our night time  temperatures easily drop to below -8 Celsius, so when you are attempting to keep an inside living space at 16 to 21 degrees Celsius for comfort, any leaks are pretty obvious on your electricity bill. Some of the more obvious culprits are generally:

  • Windows,
  • Window coverings,
  • Door seals,
  • fixture insulation,
  • water pipe insulation, and 
  • furnace efficiency

I’d argue, having lived in both extremes, heating is much more important for quality of life and safety than cooling, and improvements in the efficiency of the system and operating environment will significantly reduce the cost of either heating or cooling.

Looks like I’m running into needing another post to complete this article, part three next week will consider longer term planning that can improve the efficiency and sustainability of a house.

Thanks for reading, leave a comment if you’ve got any other suggestions!

Published by Mike Thomas

Mike Thomas P.Eng. ENV SP, is the author of and Director of Engineering at the City of Revelstoke in the Interior of British Columbia, Canada.