Posts Tagged ‘Energy Factor’

DIY: Home Energy Audit- The Mechanical System

Thursday, July 14th, 2011

You are getting through the building as a system and now you need to know how the actual brains work.

We’ve gotten through the tools you need, the safety equipment and common sense and how to prepare yourself. Then we discussed the actual building as a system. Now we’re moving on to the actual mechanical systems or what some people call the brains of the house. This would be the heating, cooling and water systems of your home.

Heating System Types

Central- In a central system, air or water is heated in one area and then distributed throughout the system by a fan or pump which is typically controlled by one central thermostat. You check these systems for issues by taking a look at the main system’s records to see when it was last serviced. Check the filters to make sure they are clean and installed properly.

Zone- In a zoned system each room or zone is a self contained system which typically has its own thermostat that controls that zone. You check these types of systems by looking at the baseboards for dust and for potential air leaks in the systems coming from the floor or wall near the baseboards.

Cooling System Types

Space Cooling- is cooling a home by planting trees to shade a home or installing overhangs in the proper way as to allow sun in yet block sun when it is not needed.  Window shades can also be used to block the sunlight and shade your home for thermal blocking. Air conditioning is not always needed, but ducting is typically run through attics and non-conditioned spaces which get really hot. By making sure that ducts are sealed properly ( use of mastic instead of tape so that conditioned air is not leaking straight out into non-conditioned space) you can save money). Another solution to space cooling is to condition an attic an properly air seal an attic and know where you want to create your thermal envelope. Remember your house as a system- take another look at the diagram above and look at all of the paces that air can leak out! Check all of the ducting to make sure that you can’t see daylight through the mastic. If you really want to try to use your incense here you can waft it into you ducts and see if you see any of the smoke coming out through holes; if you see smoke coming out through holes in your ducts, then you can see where the ducts need to have more mastic applied, as that is where your conditioned air is leaking out.

Water System- Hot water is needed to bath and wash dishes and clothes. The temperature of your hot water heater should be set to 120 degrees Fahrenheit. Many people are looking to solar hot water heater systems as they can get up to 70% of their water heated by the sun! This is a fantastic way to save money and see an immediate payback for a home energy improvement. When you are inspecting your hot water system you will want to check to make sure your first two feet of pipe are insulated. Put your hand on the shell of your hot water heater; if it feels warm, it needs a blanket- these can be purchased at big box stores.

Terms to know when looking at mechanical systems in your home:

SEER- Seasonal Energy Efficiency Ratio is the standard for air conditioning efficiency. It is the ratio of the cooling capacity to the power input. The higher the number the more cooling is achieved for each watt of electricity.

HSPF- Heating Season Performance Factor is the most important measure for heatpumps. Heat pumps also have a SEER for their air conditioning function.

EF-Energy Factor is the measure for the overall efficiency of water heaters. It includes the pilot light and standby loss from a tank. Standard gas hot water tanks have been about EF .58 – or about 58% efficient. High efficiency gas tanks above .62 EF and electric tanks above .93 EF qualify for utility rebates. Tankless water heaters range from .79 – .86 EF, while some condensing boilers and water tanks reach above .90 EF.

GPM- Gallons Per Minute is the water flow rate for faucet aerators and shower-heads. Shower-heads are available that work well at 1.6 GPM and aerators that work well at 0.8 GPM.

This is getting exciting, isn’t it?! You’re well on your way on getting through your own energy audit! Next you will find out how to go through your own attic. Why do we have attics anyways? If you have a friend who needs to get started on their own audit, too, send them to the very beginning, and get them started! It is never too late.  If you ever have any questions, or want for us to come do some diagnostics, drop us an email or find us on Facebook!