Energy Efficiency
We began working to reduce MSC's operational energy requirements long before considering the Energy Squad Energy Audits conducted on our 5 houses this November. Convincing the board to invest in efficiency is not always easy, so we provide graphic summaries of our findings.
Half the energy requirement of most residential houses in MN goes to heating in this climate.
20% goes to lighting
15% goes to Appliances
10% goes to water heating
Appliances:
Since 3 of our houses have more than 4 refrigerators, appliances may rival lighting. Annual savings from upgrading our 5 least efficient refrigerators would be $538 to $1043 based on electric rates in 2007 and 2008. In Spring, or perhaps January, MSC can benefit from incentives for trading inefficient appliances for efficient new ones.
Frequently accessed refrigerators that are nearly empty consume more energy than nearly full refrigerators. Residents who use little refrigerator volume can save energy by sharing with those who use more. From 10/?/09 to 11/26/09 L-House used only 2 refrigerators for 6 people, the 3rd refrigerator was unplugged. The oldest refrigerator (L3) left the building. Brian Ashman did the testing, and can explain the identity of any refrigerator. The MSC Refrigerators Report below summarizes the general conclusions.
Electric Space heaters found in rooms L22 and M2? are symptomatic of heating issues that are yet to be resolved. A single 1200W heater makes a significant impact on household electric use. It was suggested that proper attic venting would profoundly reduce summer heating of upstairs rooms in L-House, thus potentially making central Air conditioning unnecessary in L House (Give thanks to the Oak Trees that shade L-House).
The BOD has voted to start replacing old washing machines. The machine in M-House is the first to upgrade because it brakes down most frequently. The energy saving payback time for washer upgrades could be a long time. Sustainability committee advocates front load high efficiency energy star rated washers. Manager Dennis is looking into the costs of replacement parts for such refrigerators. We don't know if upgrading washers might cost more than maintaining the old ones we have.
We will be very interested in the NEC recommendations regarding furnaces and water heaters to upgrade. So far furnaces in C-House & L-House warrant consideration. The water heater in M-House should at least get upgraded to the tank water heater no longer in use by E-House.
Light:
Lighting efficiency is simpler. We are identifying better lightbulbs to purchase. We can switch to electronic ballasts and thinner florescent light tubes, and replace incandescent lamps with compact fluorescent bulbs for significant savings within 3 years. LEDs are also being evaluated. Below are some general comparisons among light types. An effort is being made to specify the best CFLs to purchase.
This November the Energy Squad replaced many indoor lights with 13W Maxlite Spiral CFLs that yield 900Lumens of light per Watt (69Lm/W is a very good efficiency and these are each 50Lm brighter than a 60W incandescent). The Maxlite globe CFLs in bathrooms are less efficient, only 57Lm/W (800Lumens/14W), but we've purchased spiral CFLs that inefficient. These are a great reduction in energy use. Addressing the linear fluorescents, and dimmable lights is up to us to do.
Halogens appear to be a dead end for energy savings. They consume less than conventional incandescents, but substantially more than LEDs or CFLs.
SunnyDayEarthSolutions has quality LED spot lights for $40 (Advantages: 30000hr+ life regardless of rapid on off cycles, bright at -20F, instant-on, can achieve very narrow focus) and 14W or 18W fluorescent tube replacements for $60 (Advantages: a 12W+ savings, 50000hr life regardless of rapid on off cycles). 100Lm/W 4ft T5 fluorescent lights are available for $28 per single or $35 per double at Home Depot. Noll Hardware can order Maxlite CFLs for us. NEC might be willing to sell some CFLs they get from their distributor in the future if we can't buy similarly efficient ones locally.
Insulation and Heating Efficiency:
Energy Squad found many leeks overlooked while we installed new windows in the houses. Insulation is only as good as the weakest spots in the house envelope.
The squad sealed significant leaks around at least 2 exterior doors per house, that may make significant differences. However, the blower door tests indicate serious bypass issues that may yet prevent realization of the full potential savings from our investments in new windows for houses K, E, and M. M-House is the most severe case. All but the 2 bathroom windows were replaced with energy efficient vinyl windows, yet this is still the leakiest house after fixing the door leaks. The bypass along the chimny is likely the single largest leak. Much work remains to be done, and thoughtful priorities are needed. Brian's 2009 Energy Audit Notes are below.
M-House 4800cfm <-- Had difficulty achieving -50Pa of pressure for the test
E-House 3600cfm <-- Many bypass issues.
K-House 3100cfm <-- Not horrible for such a large house. Yet, the size of the K-House Heating bill shocked the inspectors.
L-House 2400cfm <-- Just about average for it's size, though our sqft estimate seemed high to them.
C-House 600cfm <-- A reasonably tight house now that the door leaks are fixed.
Only C-House received a programmable thermostat. L-House may benefit from programming later on.
Major savings can be achieved by correcting problems with each house thermal envelope. The dollar amount is obscured by varied pricing, but we can save gas proportional to the reduction in air leakage rate. Reducing air leakage by 50% from the above values would merely approach where mechanical ventilation is needed. Obviously cutting gas use in half would require professional help, but we are studying to do much of this work ourselves.