Central Maine (207) 512-2408

Sample Audit

 

Home Performance Assessment

Home Energy Evaluation For:

Description of buildings: Ranch Style, Full Basement

Location:

Date of Energy Audit:

Prepared By:

 

  

Audit summary

I conducted an energy audit on February 00, 2014, at your home located at 21 Bedrock Drive, Augusta, ME 04330. The major reason for the energy audit was to review and assess the current method of heating and to provide energy saving recommendations. The impetus for this audit was also because of a potential natural gas pipeline extension onto Augusta as early as 2015. The audited house was originally constructed in 1965 as a modular home. The original footprint was approximately 12’ wide and 56’ feet long. This was placed on a full concrete foundation and expanded out to 24’ in width with a 1,344 square foot living area. The heating system consists primarily of a warm air furnace, supplemented with a coal fired furnace. Both are located in the basement. An “All-Nighter wood stove was in the basement but had been disconnected. Domestic hot water is heated by an electric hot water heater (wrapped).

The results of the blower door test revealed a very high leak rate when compared to a national standard. As a result, weatherization improvements, particularly air -sealing, should be considered. You indicated a possibility of your doing some of the work yourself. If that occurs, there may be alternatives to what I have recommended. With that said, my recommendations by priority include:

· *air seal and insulate the basement sill by applying 2” spray foam and fire retardant paint

· apply 2” spray foam and paint on the wall, from the sill to 2’ below grade

· *install new natural gas fired modulating boiler and panel radiator or conventional baseboard (or retain the existing furnace)

· *air seal the basement bulkhead with a plywood and 2” rigid foam panel

· insulate the stair well walls that come up from the basement with minimum R13 fiberglass

· *insulate and air seal the door to the attic

· install a heat pump water heater in the basement (secondary option is to install a propane demand water heater)

· add 12” cellulose insulation above the ceiling of west (bedroom) end of the attic

The priority items are marked with an asterisk. The important thing is to remember is that in order to receive any rebates from Efficiency Maine you have to hire a “Qualified Partner” to do the work.

 

 

Insulation

Your home has insulation that is about average for a house of this age. The walls are 2” x 4” with an R- value2 of R-11 in the walls. The attic insulation level was varied but there appeared to be no more than 6” (combination of fiberglass and loose fill cellulose). There were a lot of personal items stored in the attic masking it difficult to get around and to see the insulation amount. Other areas were covered with plywood flooring. What I was able to see, I judged an insulation level of R-19. Attics should have at least 14” total or a minimum (R-49). The basement sills appeared to be concrete blocks covered with gypsum. There was some fiberglass in place in the sills but it was quite dirty indicating it was allowing a lot of air to pass through and doing very little insulating. I recommend removing the gypsum and any fiberglass in the sill and apply two part spray foam to the sill. The basement concrete walls did have fiberglass insulation where there is paneling leaving a good portion of the exterior wall without insulation.

Spray foam from the sill down to 2 feet below grade will help here because of the heat from the furnace, but strongly recommended in the sill where a good amount of air sealing will also occur.

The basement ceiling is insulated in part with R11 fiberglass. Many homes I see have no ceiling insulation but for any living area having insulation in the ceiling will keep the space warmer if there is a heat source.

 

As an FYI, the Maine Fire Code, MRSA Title 25, section 2447, does require a fire retardant (gypsum wallboard, intumescent paint, or other approved coating to provide a 15 minute fire barrier. This has been in Maine law for 20 years. Commercial contractors use a special latex paint that is approved as a 15 minute fire barrier.

 

 

 Doors and Windows

You have two standard exterior doors and a slider in addition to a dozen wood window equivalents. The thermal imaging camera did not show a significant amount of air leakage in the doors and windows but door insulation kits will provide a better seal for the doors. Q-Lon is one type I believe is really excellent.  Air leakage (i.e., heat loss) was very apparent in the door to the basement, the door to the attic stairs, and the bulkhead. The bulkhead and attic were more severe since outside air connects directly to these areas and then to the rest of the house.

At the bulkhead I suggest a plywood-rigid foam panel be constructed in two sections (like an “L”) going horizontally above the third step to the rear of the steps and also vertically from that point up to the top of the opening. The small opening under this panel will allow warm air from the basement to warm up the bulkhead space to lessen the chance for frost to get close to the house and crack the foundation.

The house had walk up stairs to the attic. This allowed for a lot of air leakage, cold air coming in and the loss of heated air. If air sealing is done in the attic, the top plate can be sealed with canned spray foam. Also, the attic door needs to be tighter using door weatherstrip and a door sweep as well as have 2” rigid foam adhered to the cold side.

The windows were not too bad, and unfortunately, with glass, there is always the feeling of cold. Curtains or inserts will help lessen this and there are also window kits (as well as door kits) that can be ordered on-line or bought locally.

  

Blower Door Test and Air Leakage

The purpose of the blower door test is to determine the overall leak rate through the thermal envelop which separates the conditioned (i.e., heated) and unconditioned spaces. In addition, and more importantly, the test allows me to compute what the leak rate means in terms of lost fuel.

 

The following are the results of the Blower Door Test:

· At negative 50 Pascal, there was a measured air leak rate through the fan averaging 4,933 cfm; with an equivalent hole size of 509 in2 or 12" by 42”. This rate, for your size home is considerably more than I usually see. As stated earlier, a very large amount of heat loss is coming from the attic and the basement where outside air has many opportunities to pass into the living space. The cat door was closed off during the test.

· I computed the natural air leak rate to be approximately 267 cfm or 1.49 ACHn (air changes per hour). The leak rate through your walls was about 470 cfm per 100 sf of wall. A target in a newer home is less than 25 cf/100 sf and less than 1 ACHn.

· I have estimated the equivalent amount of fuel lost through excess air leakage. In terms of Btu’s I calculated that this to be 41 million Btus. In terms of fuel oil this represents approximately 295 gallons, and at $3.75/gallon = $1,106 annually. This is considered excess leakage.

 

· An acceptable leak rate according to the 2012 IECC Energy Code is not to exceed 3 Air Changes per Hour (ACH) at negative 50 Pascal (i.e., the house pressure during the blower door test). The loss during the blower door test in your home was had an ACH of ~13.

 

 

Space Heating and Hot Water

Heat is supplied by a 1982 Olsen oil fired furnace, model BCL and a U.S. Stove Company model 1357M coal stove. The furnace is rated at 115,000 Btu/brand feeds warm air to the supply ducts. The coal stove has an 85,000 Btu/hr capacity but did not appear to be passing very hot air to the living space. The literature on line indicated it might possibly have to do with the fact that the furnace and the stove join and perhaps there is an issue with the draft. I understand the coal stove is being used to use up the coal at this point. The furnace is about 22 years old and has several more years of use. I know you are considering a switch to natural gas next year if a connection is available.

From a cost standpoint, you will get more return on your dollar by addressing the heat loss first.

Interestingly, propane is less costly than natural gas now and the price of natural gas is likely to be high for a while. Your furnace has a factory efficiency of around 83% when it was constructed. It you tape the duct seams with metal tape and insulate the ducts you will get more heat to the living space. I did not do an efficiency test on the furnace but I suspect it is around 80-82% and annual services will always keep the efficiency up close to this number. In short, the furnace might be worth keeping. If you want to install your own panel radiators or baseboard, a new boiler is your only option.

Domestic hot water is provided by an electric water heater. As you know these are inefficient from the standpoint of the cost to heat water. An option I suggest is a heat pump water heater. While these heat water using electricity, the heat pump on top on the unit considerably reduces electrical use. At the same time this will dehumidify the basement in the warmer weather somewhat.

If you go with a new boiler then heating domestic hot water with an indirect fired water heater becomes an option. These are typically $2,200 or more. If you stay with the furnace you could go with the HP water heater.

 

Heating Efficiency

To assess heating energy, I look at what is called a Home Heating Index, or HHI. The home heating index is the amount of Btu/sf-heating degree day (HDD).

For central Maine the number of HDD is approximately 7,500 although it does vary some year to year. Based on the actual amount of oil (not counting the coal) your Home Heating Index computed to about16 Btu/sfheating degree-day. This is relatively high compared to most Maine homes. I attribute this to the high blower door number which is directly related to the heat loss.

To put the HHI in perspective it is not unusual for homes in Maine can have a HHI of 10-12 or higher. Some really leaky homes such as you home can have an HHI as high as 16. New homes are usually around 3-8. The leak rate is clearly the reason your HHI is so high. This index is not a hard and fast rule but rather a tool to assist homeowners in determining the need for air sealing and insulation.

 

 

 

The procedures I used to make these estimates are consistent with criteria established by the U.S. Dept. of Energy and the applicable Efficiency Maine Program standards for energy evaluations. Actual installation costs and savings may be different from estimates contained in this report. The total estimated energy savings from installing more than one measure may be less than the sum of energy cost savings of measures installed individually but this gives you an estimate as to the likely costs. Projected savings are estimated based on fuel costs of $3.75 per gallon unless otherwise stated and does not account for current or future price variations or inflation.

 

 

Disclaimer - The information contained within this report is based upon a walk-through assessment of the home on the date of the audit. I have based my findings and suggestions on what I observed at the time, data I was provided with, independent studies performed by vendors I have researched, and in some cases what was provided to me anecdotally. The suggested courses of action are my opinion and in no way am I guaranteeing installation, performance, or a specific energy savings.