The best path to a net zero or energy producing home
July 29th, 2009 by Matthew Leonard
With eminant rising energy costs, more people are looking to minimize or eliminate those ever increasing monthly payments to the utility. Some longer term thinking people are actually figuring out that they can become a utility themselves and collect money versus paying it. All of those people are our customers and they love comparing their utility bills with their neighbors.
- Does it cost a small or large fortune to get to this level?
- Will your home look strange and without windows to get there?
- Do you need so many solar panels on your roof that the reflection blinds pilots as they fly over?
This simple answer to these questions is “no” but I’ll go into more detail to better explain that.
Any home can be a net zero home or an energy producing home. The only thing you need to do is add sufficient solar photovoltaic and solar hot water panels to offset your monthly usage. Don’t get me wrong, we love the clean energy produced by solar panels but considering the first question above about net zero costing a fortune, in this case, it most likely will. If a house is wasteful, then it will need a lot more of the relatively expensive solar panels to compensate for the waste.
The Best Path to Net Zero
The obvious solution is to have a home that is maximized in its energy efficiency to greatly reduce the need for extra solar panels. But we take this approach a couple of steps farther. We work in three cost effective key areas to focus on what will improve a home’s efficiency to a point where very few solar panels are required to bring the home to net zero or even energy producing level.
Maximized Insulation and Air Sealing
Most builders will conside insulation as important but are so stuck in old ways of doing things that they can’t see there are better more modern ways of building the shell. With proven progressive materials and methods available today like Structural Insulated Panels and super insulating foundations and agressive air sealing techniques, we can build homes that use only a fraction of their stick framed counterparts.
- 6″ or 8″ thick Structural Insulated Panels (SIPs) plus 1.25″ exterior foam.
- 2″ to 8″ thick EPS foam over foundation walls.
- 2″ to 6″ thick EPS foam under basement floor.
- Icynene filled box sills and heel.
- Icynene layer over the ceiling with blown-in cellulose over top.
- High R-value windows (up to R-11.1) to keep the heat in.
- Making sure any potential exterior shell air leakage point is properly sealed.
Maximized Passive Solar Design
Passive solar design should be a no brainer but so many designers and builders neglect this important benefit. Using the best size and type of windows on the various sides of the home with proper overhangs will maximize the effectiveness of the free heat energy from the sun. Placing the home on the lot in a way that will improve the passive solar characteristics of a home is critical to its success.
- High solar heat gain yet high R-value windows on southern exposure to bring in more winter solar heat and keep it in once its in.
- Low solar heat gain windows (which perform better than low E) on north, east and west exposures to keep out summer heat.
- Main living spaces on southern side of home.
- Garage and minimal windows on northern exposure.
- Double drywall in southern side rooms to store solar heat energy.
Minimize the Energy Load
Reduce the consumption of energy required to operate the home.
- Because of the maximized insulation, air sealing and passive solar design, a much smaller geothermal heating & cooling system in required. On top of the smaller size you get up to 500% efficiency.
- Compact Fluorescent lighting (until LED lighting is more cost effective and efficient).
- On-demand or solar hot water heater.
- Energy Recovery Ventilators (ERVs) are used to give regular fresh air exchanges to the home while recovering over 70% of the heat that would be lost through ventilation. We maximize the ERV’s effectiveness by using a hot water pre-heater from the left over heat generated by the geothermal heating system.
We have found that by following the above priciples of maximizing insulation, air sealing and passive solar design while minimizing the home’s energy load, we can build a net zero or energy producing home at a cost per square foot that is well below a home that doesn’t focus on those key areas but just adds excessive solar panels to make up for the waste.
To see a couple of homes that follow this philosophy click below.
Tags: Energy Producing, Net Zero
This entry was posted on Wednesday, July 29th, 2009 at 11:45 am and is filed under Energy Efficiency, Green, Save Money, Structure, Uncategorized, Windows.