Project: Energy Retrofit
Energy efficiency is the cornerstone of any green building project, whether you are remodeling a kitchen, designing an addition or upgrading your appliances. A well-designed and green-built project consumes as little energy as possible and uses renewable sources of energy whenever possible. Lower energy use not only saves you money but also has a broader societal benefit, including fewer disruptions in energy supplies, better air quality, and reduced global climate change.
Here are some broad steps to consider before you get started:
An energy retrofit requires you to make countless decisions. If are serious about a deep energy retrofit you might want to hire your contractor first and have them there when the audit is being conducted. It is a very technical process that will yield lots of data. The biggest challenge is deciding what to do with all the information you get back. The audit will tell you what needs to be done but not when or how. Prioritizing your upgrades is the challenge you and your contractor have to figure out.
We find that the most successful remodels take the time before they begin the project to get in writing what they want to get out of their project. Using the information you lean from an energy audit can help you make a more informed decision. It’s best if each household member answer these questions individually. The whole house should then have an informal meeting to share answers and create a shared vision for the project.
Basic Building Science - Thermodynamics
The intention of green building is to use all of the laws of thermodynamics to our best advantage. We can incorporate as much as insulation as possible to reduce to conduction of heat to the environment; reduce drafts by sealing the house well and incorporating ventilation where and when we want it, by directing and controlling convection; and we can take advantage of the radiant energy from the sun in winter through passive solar design.
The following are some terms to give you a better understanding of how your house works.
Conduction - heat flows through material. Insulation slows the rate of conduction and is a better insulator than wood.
Convection - heat transfer in a gas (air) or liquid by the circulation of currents. Drafts form at single-glazed windows because the windows cool the air, which gets heavier and moves down the window and across the floor.
Radiation - energy radiated or transmitted as rays or waves (or particles). Warm surfaces radiate toward cold objects.
Ventilation - the way we manage the air inside the house. We want to control how much air enters the house, where it enters the house, and what we do with it once it is there.
Once you have all the information in hand you need to decide how far you want to go and what your budget is. Remember that energy retrofitting your home is an investment not a cost. And it is a great investment today. What stops most people is not knowing what to do and who to call to achieve their goals.
Write Down Your Energy Saving Goals:
- Is your primary motivation to improve comfort?
- Are you determined to reduce your energy bill?
- Are you looking to do your part to slow down climate change?
- Are you concerned about the future affordability of living in your home?
Your answers to these questions will start to determine you priorities in home improvement projects. If you have a contractor already you can discuss options and costs for the project. If not you may want to assemble your team yourself.
Determine your Sustainability Goals
- Remember that as you tighten up your house, indoor air quality becomes more of an issue. Use only products that don’t compromise your home’s indoor air. Keep formaldehyde to a minimum.
- Make sure that there is sufficient ventilation designed into your project
- Be very careful when insulating existing walls that you don’t create an environment behind the drywall that will allow moisture to get trapped there than can lead to mold problems.
- Resource efficiency is important for some homeowners. Cellulose is primarily recycled newspapers. Fiberglass insulation has a high embodied energy (it takes a lot of energy to make glass fibers) but can use recycled glass for up to 30% of the material.
Depending on the size of your project you may need several different professionals on your team. If you are thinking of building an addition at the same time you may want to start with finding a green architect. You want one who specializes in home remodeling and has extensive green experience. Where you live will determine how broad the field of experience is.
Another option is to hire a design/build remodeling firm. Again experience and certification is very important so you can be confident they know how to approach your specific job.
If you feel confident you understand the audit and what needs to be done with your house you can hire specific trades yourself.
- Look for an insulation contractor who has been trained in the installation of cellulose and/or spray foam
- Find a good window company that can help you decide which windows are best for your home, not just what they want to sell. A simple question is how would they specify south facing windows differently from other orientations. Home shows are a great place to compare one window type to another.
- Talk to a variety of heating, ventilation and air conditioning contractors. There is a world of difference between a company that has been doing the same thing forever and one that has kept up with the times and has been trained to size equipment to the actual conditions of your house.
- Start exploring local solar companies. Some have been in the business for a decade or more and others are “Johnny-come-lately” companies that see there is a buck to be made in the solar business. The last thing you want is an electrician doing your roofing or a roofer doing your electrical installation.
Overall it is best to assemble the team and talk to them all at once about your game plan, whether it is with your contractor or on your own. If they all are on the same page and understand what you are trying to do they will work together much more efficiently and it will save you money.