Attached is a photo in my basement showing uninsulated concrete block wall. The length of one wall is 28 feet and 2 feet of it is above grade. Using the outside temperature of 12 degrees outside and 47 degrees inside with an R-value of 1 for an 8-inch concrete block I can calculate the heat loss through the top 2 feet of wall. My calculations did not take into account the windows, just for simplicity’s sake. The square foot of that portion of the wall is 2’ x 28’ or 56 sq. ft.
Total BTU loss/Hour: 1,960
Total BTU loss/24 Hour: 47,040
By adding 1" of Polystyrene board at R-5 per inch raising the R-Value of the wall section to R-6 the losses change to:
Total BTU loss/Hour: 326
Total BTU loss/25 Hour: 7,840
It would be simple matter to calculate the SIR when adding the polystyrene board and see how much payback in heat savings could be achieved.
Calculating envelope energy loss is simpler than I had imagined. At least to a reasonable degree of accuracy using the basic formulas outlined in the course. We’ve had an energy rater doing all of this work for us using software and methods that are likely more accurate but the simple formulas presented here are good enough to do a quick analysis of a home’s energy loss (along with the formula for calculating loss due to air movement through the building assembly) to determine where and how best to eliminate energy loss. The information in the course also helps determine the priority of where to tackle heat loss for the most gain for your dollar–determining the SIR, for instance.
This photo shows smoke stains on the fireplace from backdrafting in a newer home. This home was relatively “tight” and it was not surprising to find backdrafting issues in this home due to the pressure differential between the indoors and outdoors. It is likely and was advised that the damper in this fireplace be properly cleaned and maintained so that it shuts sufficiently to prevent conditioned air from escaping right up the chimney and vice versa.
InterNACHI
Calculating Envelope Energy Loss course
Library Article: Ghosting
Ghosting, is when small particles are deposited on surfaces in the home. This is most commonly found around areas of air movement. Where particles in the air are drawn through a draft fan for example and may adhere to the wall or ceiling around the fan. As discussed in the article, walls above baseboard heaters are also a common area to find “ghosting”.
In our area about 5 years ago we had a class 3 tornado go through. Homes that seemed to be fine on the exterior it was discovered the blown in insulation in the attic was all blown to the center on a heap in some cases 5 feet deep
Heat loss for surface area:
The formula for surface area heat loss per hour is (A x ^T x t)/R.
This calculation assumes an HDD of (70 – 1) taken from the degree chart for US cities.
Assuming 10% of wall area is windows the A = 2381, T = 1 t=1hr R= 19-10% or 17
So( 2381 x 69 )/17= 9664 BTU’s per hr for the walls
R 38 in ceiling less 10% (effective r value) is approximately R34
Ceiling (1476 x 69 x 1)/34 = 2995 BTU’s per hr heat loss
I am not sure if the number ^T is correct,but that is what I found from the HDD charts for US cities.?
Firestops
The purpose of firestops is to help limit the spread of fire between floors or units of a building.
Firestops can be made of metal, fire rated sheetrock, certain mortars and materials called intumescents, (materials like graphite that are fire retardant and expand when exposed to heat.
Firestops should be located where ever holes are drilled to allow passageways for plumbing, venting or electrical pipes to pass from one floor to another. In condos and townhomes the dividing walls between units need to be separated by firewalls from the foundation to the underside of the roof. Inspectors should check for any penetrations through these barriers in the attic space.
This is an infrared shot of a vent that was well below the 20 degree delta T, clearly struggling to cool the room. Without proper climate control system performance and setup, the energy loss improvements made to the home will have a minimal impact.
Simple and cost effective solutions can be made to improve energy conservation, such as adding weatherstripping to exterior doors or caulking exterior infiltration areas such as doors and windows. Energy efficient appliances and mechanical equipment should always be considered to offset the cost of energy.
This is a Infrared picture of a non-IC rated high hat light fixture during summer month with blower door activated causing hot attic air to be drawn into the homes interior living space. The result shows drastic infiltration of heat because the IC lights rating require a three inch space be maintained around fixture because they cannot be next to insulation. This means a twelve inch un insulated hole is left open to allow cool and heated indoor air space to escape. Always check can lights and recommend them to be IC rated to avoid this mess or better yet avoid them all together when possible.
Ten easy ways for homeowners to save energy as defined in the article.
Heating and cooling>Use ceiling fans instead of AC units whenever possible, Lower the thermostat one degree and save two percent for each degree it is lowered, install programmable thermostats.
Install a tankless water heater and save on the energy biills, plus have hot water instantaneously on demand. These devices use far less energy to run.
Replace incandescent light bulbs with CFL, Led or other energy saving bulb types. These bulbs use 50-75 percent less energy.
Seal and insulate- Adding insulation and air sealing all open holes around the home allow you to save on the heating and cooling bills.
Install efficient toilets and shower heads- These newer options allow you to save on water usage.
Appliances and electronics- Appliances should be replaced with Energy Star rated units, Battery and charger units with nothing connected to them should be disconnected. Computers should be shut off when not in use.
Daylighting- Use natural light when possible such as skylights to lessen the need to have electric lights in use.
Doors and Windows- Weather stripping and using blinds or other window coverings helps to keep air infiltration in these arears to a minimum.
Cooking- Use lids on pots and make meals in microwave. Convection ovens cook quicker and use less energy.
Laundry- Never use medium setting and only do full loads. Avoid high temperatures above 103 degrees and clean lint traps on dryers.
The picture attached is of an attic I inspected this past summer. Lots of times the attic is under insulated in my area. This attic was well insulated, with 12 inches of blown in fiberglass insulation. The standard for our area is roughly 10 inches so he has a well insulated attic space. The attic space was well ventilated and had an even amount of insulation throughout.
Residential Basement Insulation was a valuable article about insulating the basement. Upwards of 50% of heating loss can occur in a conditioned basement that is not insulated. There are 3 forms of insulation for basements. One is to insulate the interior with a rigid foam board, spray foam, or batting. Second is Exterior insulation by means of a rigid foam board on the exterior of the concrete walls. Third is the foam form foundation system. This system uses stacked foam forms with which concrete is poured down the middle.
While all these options better insulate the home, there are some concerns as well. Termites can eat into foam, so exterior and foam form insulation is susceptible.
The article also shows that insulating an unfinished basement still helps lower heating and cooling costs. It also recommends keeping rigid foam out of the direct rays of the sun, due to the degrading effects of sun light.
Since I could not upload file from word 2016 on R-Values for Insulation from the Energy Star. Gov. web site, I"ll give the info for the Zone 5 , Michigan, since I live there. R 49 to R60 for a uninsulated attic. Existing 3-4 inches of insulation , add to attic, R38 to R49. Floor, R25 to R30. Zone 5, Michigan, add R5 insulative sheathing before installing the new siding.
These are the outside air-conditioning compressor units. Both are mounted on pads and are properly supported and level. The electrical disconnect is in sight of the units and the refrigerant return lines are insulated (although not completely visible in this picture). The units appear to be operational and are clear of debris or obstructions which might affect airflow.
Read article on Insulation R Values. Concerning crawlspace walls. Conditioned,
according to Owens Corning web site zone 5 where I live, Michigan, R19 unfaced batts on walls and extending two foot over on crawlspace floors. Fill in bays between floor joists at band joist with R19. 6 mils or > of a vapor barrier on floor lapped 6 inches over joint and 6 inches up wall sealed on walls and joints. Seal all gaps or areas where the floor sheathing meets at the edge of the band joists before insulating. Any other areas , like the electrical or plumbing penetrating through the band joists. Again, don’t compress the insulation if all possible, so the R-Values are not reduced.
Disturbing insulation and not properly air sealing retro work in an existing home can dramatically reduce the R value of a crawlspace. Often when ducts or electrical work is added or system upgrades are installed in crawlspace, often the contractor does not notify the homeowner that their insulation has been disturbed. Low and high insulation will cause many problems in the building envelope, as well as added energy costs.
Article insulation R-value. In order for R Values to apply correctly to insulation, the insulation must be installed correctly. If wall cavities are filled with Batt insulation that was compressed to fit the wall cavity, the R Value is compromised. It is very important that insulation is properly installed in homes, thus without voids or being compressed, which lowers the R value.
