Sunday, February 12, 2012

Design Priorities for Energy Efficiency

Energy efficiency starts with good design. Of course the efficiency of nearly any home can be improved, but designing for energy efficiency is always going to yield the best results. 
Depending on the status of your project, there are priorities to consider that will have an impact on the energy performance of the structure.
1. Property Selection - View lots are the most common to create challenges with home energy use. Ideally southern views are going to be beneficial and western views the most detrimental. Additionally the shape of the lot can affect the length axis of the home with positive or negative effects on energy use.
2. Solar Orientation - Once property has been selected, the structure should be oriented to capitalize on the seasonal arc of the sun. In the northern hemisphere it's preferred to orient windows to the southern exposure and prevent heat gain on the east and west elevations.
3. Passive Solar Design - The sun can heat our homes in the winter and even help keep us cool in the summer - for free, when passive solar design techniques are used. In this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air created by exposure to the sun. Passive systems are simple, have few moving parts, and require minimal maintenance and no mechanical systems.
4. Reduce Energy Demand - Some of the most effective methods to reduce energy use include: increased insulation values and weathertightness; HVAC zoning and programmable thermostatsCFL and LED lighting; and behavior modification.
5. Increase Efficiency - Increased energy efficiency is available for a number of building systems. This is where cost-benefit analysis becomes important. Depending on the success of the previous strategies, there may be a point of diminishing returns from the investment in higher performance products. Windows and HVAC systems are the main items to fall into this category.
6. Solar Thermal Heating (and Cooling) - Solar hot water heating is a type of thermal heating strategy but did you know that thermal solar collectors can also be used to heat the inside of the house? This is called hydronic heating and is actually quite comfortable and can be affordable. Additionally, in the right application solar thermal panels can actually be used to cool your home in the summer time.
7. Alternate or Renewal Energy - The final upgrade to consider is the addition of an alternate energy source like photo-voltaic panels or a renewable source like a micro-hydro generator. Recent industry articles indicate the cost of PV (photo-voltaic) over their lifetime, is getting close to power purchased from utility companies. Additionally, if PV panels are amortized over a 15-year mortgage period, the cost saving and interest tax deduction may exceed the cost of purchased power. Let us help you make the calculations.