Energy Improvements and Your Home

We are a general contracting, plumbing and weatherization company who is working in residential and commercial market in East Tennessee area. Through a variety of tests, we can tell a customer not only what measures should be done to improve the efficiency of the home, but also what the return on investment will be. Apart from the energy savings, we also pay particular attention to the health and safety of the home.

Energy auditing and building analysis is a fairly new industry. I received my training in Memphis, through Amerispec, a Building Performance Institute’s affiliated program.

The Building Shell (Air Sealing)

All homes have an air barrier, but some are, of course, better than others. An air barrier basically helps to reduce the amount of conditioned air that is lost and replaced by unconditioned air. The faster a building exchanges air with the outside, the more energy is needed to maintain the structure at a comfortable temperature. There are always holes in your air barrier, because otherwise you would suffocate in your home. The trick is to keep the number of holes to an acceptable level without compromising safe and healthy ventilation.

We use a blower door, which is essentially a door frame, tarp, and fan that goes in an exterior door, hooked up to a pressure manometer. Basically, this test gives me the CFM leakage of the structure at 50 pascals of pressure. While the fan is running, We can typically find leaks using various techniques and equipment. Based on the structure, the leakage number, and the subsequent tests, We then determine if it is safe to seal up the house further, where to seal, and what potential savings are to be gained.

In our experience, older homes tend to be leakier than new homes. Air sealing in the attic is typically the best place to start. Recessed lights, plumbing chases, wire intrusions, open wall cavities, and attic hatches are common leakage points. If you are sealing a recessed light, make sure you follow local fire code.

If you would like to learn more about specific air sealing techniques, the Department of Energy link below has some good information at this site.

ROI on Air Sealing – AVG 18%
(It really varies on the structure, energy prices, how difficult the air sealing techniques are, and how good your contractor is at finding and sealing the biggest leaks. The materials are usually inexpensive, but can use a lot of labor)

 
Insulation

Your thermal barrier, or insulation, will determine the ability of your home to retard heat flow. The slower your heat leaves your home, the less energy your heating system will use. Your air barrier and thermal barrier should be together and continuous for maximum efficiency. It is very important that you air seal before installing new or additional insulation. Insulation is another job We would recommend hiring a trained professional before tackling.

The typical insulation install in an existing home is installed in the attic. Sidewalls and rim joists can also be done in certain homes. It is important to do the proper attic prep before adding any insulation. This may include the following:

  • Determine amount (usually R-38: about 11 inches of blown cellulose or fiberglass.)
  • Check electrical (Watch out for knob and tube wiring, or any frayed wires or overburdened junctions.)
  • Make insulated boxes to go over any non-IC-rated recessed lights
  • Metal flashing with fire-safe caulk to keep insulation away from chimney or flue
  • Air sealing all intrusions into attic (If air sealing is not done, condensation can occur in attic, leading to mold, derated insulation, and ice dams.)
  • Ventilation (Make sure soffit vents have proper vents to train air flow to ridge vent and also make sure blocking is installed to prevent new insulation from clogging vents. Installing insulation without proper vents and blocking can lead to wind washing that will derate your insulation.)
  • Dams may need to be installed to prevent insulation from spilling over attic hatches, air handlers, and vents
  • Any roof leaks must be addressed
  • Watch out for vermiculite, as it has been known to contain asbestos, which can cause cancer. It should be removed by an asbestos-removal contractor.

 

Blowing sidewalls and floors can be a very difficult job, and the only houses that typically make sense to do this in are those without insulation that have large wall cavities and balloon framing. This is definitely a job for the professionals.

Rim joist insulation can be an effective install for those homes with uninsulated rim joists. Below is a nice video that shows where the rim joist is. A homeowner or even a contractor can simply use rigid board insulation, friction fit and foamed on the edges with cans of spray foam, for sufficient improvement. The more expensive spray foam with the large canisters in the video is not necessary. 

We personally prefer to use loose blown cellulose insulation. It is essentially recycled newspaper.  We prefer this to fiberglass as it is non-toxic, resists air, and will seal small air leaks, where fiberglass will not stop air and is quickly derated when windwashing is present. I do use fiberglass on occasion, and it is certainly an effective form of insulation. Closed-cell foam insulation is the “new kid on the block.” It is a perfect air barrier with a high R value, but it is expensive. It is a good to use if you are insulating a roof deck where you are bringing the entire attic inside the thermal envelope; for example, when you have ducts and an air handler in the attic.

(photo: Cellulose Insulation)

ROI on insulation: AVG. 17%
(Varies depending on difficulty of the install, and how much insulation there is. The less existing insulation there is, the higher the ROI.)

 
Duct Sealing and Insulation

If your ducts are entirely inside the thermal envelope, or conditioned area, this is typically not a problem. You can seal ducts in this situation to help balance your furnace. This becomes critical when you have ducts in a crawl space or attic. Any leaks in the ducts will help to heat that attic or crawl space. This can, of course, waste energy, but it can also lead to condensation issues, as the conditioned warm air hits the cool roof deck or crawl space. A very easy fix for sealing your ducts is to use duct mastic to seal up all the joints and connections. Mastic is good because it does not come off like tape and can expand and contract. It is a paste that can be spread with a brush or just an old glove that you are willing to sacrifice.

Ducts in unconditioned spaces should be insulated to R-11. It is possible to lose 10-30% of a home’s heating and cooling energy through the conduction of uninsulated ducts.

ROI on duct sealing: AVG 14%
(Varies on fuel type, prices, accessibility, but also offers many residual benefits to the HVAC.)

ROI on duct insulation: AVG 22%
(Varies on fuel, prices, job difficulty.)

 
Water Heaters

The first thing to look at is the temperature. 120 degrees usually works well. Make sure your water is not hotter than that. You can check the water heater, as some do have settings, but you may have to put a thermometer under hot water to find out. Constantly keeping a tank at too high a temperature is extremely expensive.

The second thing to be concerned about are the water pipes. Are they insulated? If not, insulate starting from the tank, 6’ on the cold side, and as much of the warm side as you can reach. This will help you reduce standby loss, and it is super easy and cheap also. In some situations water heater tank wrap can also be installed, but be careful because in some water heaters, a wrap will void the warranty. Make sure to check the manual to find out if a wrap is appropriate. Most new water heaters are already insulated.

Should you consider replacement? If you have an electric water heater, We would strongly recommend the new air source heat pump water heaters. They use less than half the electricity of a traditional electric water heater. Solar hot water is another nice option, especially those that are concerned about steady supplies of traditional energy in the future. On-demand tankless systems work well if you use natural gas for your water heating, especially if you are moving from an inefficient tank model (non-condensing unit, atmospherically vented). However, with natural gas so cheap, the ROI is not great, and if you have a heavy hot-water need, you may need more than one.

(photo: Air Source Heat Pump Water Heater)

ROI pipe insulation- AVG 27%
(Big ROI because improvement is so cheap)

ROI new air source heat pump water heater- AVG 23%

ROI Solar hot water- 7%-15%
(Varies based on fuel, can be higher with rebates)

ROI tankless Gas- 4%-7%
(Varies based on type replacing, fuel prices)

 
Water Conservation

Low-flow showerheads, faucet aerators, and low-flow toilets are a great way to save water, along with whatever fuel you are using to heat your water, as well as your sewer bill. Most showerheads will tell you on the head how many GPM they allow to flow. Low-flow showerheads typically allow 1.5 GPM. If you have a showerhead with 2.0 GPM of flow or higher, it is a good idea to replace it with a low-flow showerhead. Bear in mind that you will have less pressure and water with a low-flow head, although the new designs do a good job of aerating the water. Low-flow faucet aerators are also 1.5 GPM. It is a good idea to replace the aerators that are 2.0 GPM or higher. The aerators are super cheap, and you will not sacrifice anything to achieve the water savings.

Low-flush toilets typically use 1.6 gallons per flush, although I have seen lower, while older toilets can use 3.5 GPF. There are also dual-flush toilets that allow even lower GPF for liquid waste. Switching to a low-flow toilet can save 20,000 gallons of water per year. Composting toilets are a good solution for those off the grid, or who want to remain independent of the public sewer.  

(photo: Aerated water)                 

ROI low flow showerhead: AVG. 50%
(Varies, dependent on fuel source, water prices, GPM of former head, and water use)

ROI Faucet Aerators 1.5GPM: AVG. 70%
(Varies, dependent on fuel source, water prices, GPM of former head, and water use)

ROI low flow toilet 1.6 GPL: AVG. 28%
(Varies, dependent on water prices, former GPF amount, and sewer)

Health and Safety

CO and moisture/mold are the two biggest things that We are concerned about, as far as health and safety, when we are looking at a house. We can always tell who has a wet basement when we drive by a house and see relatively new paint peeling off. This is from the vapor pressure of the moisture. Excess moisture will literally take years off the life of your home. Below is a list that we give my clients to help them to keep their house safe, healthy, and durable.

Living in a healthy home and avoiding mold and mildew:

  1. Avoid unvented space heaters
  2. Don’t overcool the house in the summer
  3. Don’t hang drying clothes inside
  4. Don’t dry wood indoors (no storing firewood inside)
  5. Use kitchen and bath fans at least 3x the duration of shower or cooking
  6. Enhance room circulation with fans to avoid cold spots
  7. Avoid storing items against cold outside walls or in damp basements
  8. Avoid storing vulnerable materials in damp basements
  9. Run a humidistat equipped dehumidifier during summer in damp basements
  10. Additional pets and people add moisture; be aware of increased ventilation needs if adding occupants.
  11. New construction adds tremendous moisture to home for the first 2 years as materials are drying
  12. Make sure dryer is always vented outside
  13. Never store the following inside: paints, solvents, grease, oil, pesticides, gas equipment, kerosene space heaters
  14. Don’t warm your car up in the garage, if garage is attached to the house. 
  15. Beware of too many house plants, as they can add a lot of moisture to the home
  16. Make sure drain pipes are functional and sent away from the foundation (also keep gutters clean)
  17. Have heating equipment professionally maintained

 

 Doors and windows

We have never sold a new window job, because the ROI is always terrible. The window industry certainly has some great advertising, because more often than not we have clients who think they need new windows. If you have old wood-frame single-pane windows, you are better off caulking, weatherstripping, and adding storm windows. If you already have double-pane or better windows, then simply caulking and weatherstripping, if needed, are sufficient. Doors are in a similar situation; just weatherstrip and make sure the door sweep is in good condition. The only time we would replace a door is when an interior door is used as an exterior door, but even then the ROI is not great. This is sometimes true if you have a door to the attic or to the garage. We have done the ROI calculations for window jobs for those past clients who would not take my word for it. See below:

ROI new windows: 3% AVG

 

 

Resource List