Energy Efficiency FAQ
Home energy efficiency is a series of steps and lifestyle changes that the homeowner undertakes to do all the household tasks as before while using much less energy thereby resulting in a reduced utility bill and lower carbon footprint.
Usually it can be broken down into three basic steps 1. Simple lifestyle changes. 2. Light efficiency measures and 3. Heavy efficiency measures. The steps become progressively costly and complicated but the resulting energy savings also increase.
All types of energy be it electricity, natural gas or gasoline can be saved by executing various appropriate efficiency measures. Sometimes efficiency can be obtained by switching from one form of energy use to another. For example electric vehicles are much more energy efficient than similar sized gas vehicles.
For this the homeowner needs to have some idea regarding how much energy a particular device of task is consuming in the house. Then he can effectively compare before and after energy consumption patterns to arrive at a conclusion. For this various energy measuring devices like a kill-a-watt meter can be used. A whole house energy audit made by professionals also comes in handy. In general the space conditioning and water heating tasks consume the majority of energy in a household and provides the most opportunity for energy savings.
This means the most value for money is obtained when doing the initial steps of saving energy. After the initial easy and cheap steps are taken saving more energy gets progressively more difficult and the payback period of the extra investment on efficiency keeps on increasing.
This will vary from household to household but typically a 5-10% savings throughout the year is possible.
LED bulbs are 86% more efficient than old incandescent bulbs and twice as efficient as CFL bulbs. By switching from incandescent bulbs to LED, a household can save $50-150 per year. Since the cost of such bulbs are now in the $2-3 range, the payback can be as low as a few months.
A smart strip is an intelligent multi-point electrical outlet that has some extra electronics to create master and slave outlets. It monitors the master outlet continuously and when the appliance connected to it is switched off it completely cuts off power from the slave outlets thus removing the power leaching due to stand-by or idle power. For example in case of a computer system the desktop CPU can be connected to the master outlet and all peripherals and monitors to the slave outlets. This stand-by power leaching is usually small but they add up over numerous appliances and over time. A typical home can save close to $100 yearly by installing such devices. The payback can be less than an year.
Using these host of measures a household can save about $20-25 monthly on the utility bill. Since these measures will cost a total of under $500, the payback is swift and the effort needed is also minor.
Typically insulating either the roof or wall or floors cost thousands of dollars in material and labor and about a week worth of effort. It can save about $500-1000 in space conditioning costs in a year. So payback can be in the order of 10-20 years. However, note that without this step it will be almost impossible to get to net-zero energy using rooftop solar as there won’t be enough roof area for the panels needed to offset such huge energy requirement.
Again it depends on the size of the house and the number of windows but typically the costs are over ten thousand dollar and it is a major decision from the homeowner.
Steps to use
These are steps that any homeowner can take without spending any money. It is a different way of doing things than before that leads to energy savings.
Switching off unnecessary lights, unused computers, and appliances, using full loads in dishwashers and washers, setting programmable thermostats to 68F in winter and 78F in summer, taking shorter showers, and washing in cold water with high efficiency detergent are some example steps that conserve energy but do not incur any costs.
These are steps that incur some minor costs and effort but result in substantial energy saving throughout the year.
Some examples are switching bulbs to LED, installing a smart thermostat, using smart strips, weatherstripping and caulking, and installing low-flow faucet aerators and shower heads.
A smart thermostat lets the homeowner program the times when the house needs to be conditioned – that is either heated or cooled. By not using space conditioning when the house is unoccupied, the homeowner can save substantial amount of energy in both electricity and natural gas. Certain modern ones come with WiFi connection and can be monitored and activated remotely. Also such thermostats can learn the household occupancy pattern and automatically program themselves. The smarter the thermostat the more energy it can save. Typically space conditioning consumes 40-50% of a household’s energy and so this is a very big deal.
They are effective because they reduce the use of water and more importantly hot water thus saving energy in the domestic water heater. They are usually labeled by the federal water efficiency standard called “Water Sense”.
These are available in the hardware store and can be used along with caulking to prevent leaks around doors, windows, power outlets etc. Preventing such leaks makes the house more energy efficient from space conditioning point of view.
These are steps that are costly and time consuming but also results in substantial energy savings. The homeowner needs to carefully consider the payback before undertaking such steps.
Heavy efficiency measures include ceiling, floor and wall insulation, double/triple pane
windows and energy star appliances.
Insulation in the housing envelope reduces the heat loss to and from the interior of the use much like the principles of thermos flask. This in turn reduces the energy needed for space
conditioning – not only heating but also cooling in summer. Typically newer houses have already insulation built into the code but the older houses might have little or no insulation. Insulating the roof from the attic is the easiest through fiber-glass bats or spray in cellulose.
Walls are also doable by drilling some holes and injecting cellulose. In case of houses with crawl space the underneath can be covered with spray foam insulation. However, houses on concrete slabs have no easy way on insulating the floors.
R-value is the measure of how effective is an insulation material is preventing heat loss – the higher the better. Typically recommended values for roofs are R-40 and walls is R-30.
Again single pane windows are very poor insulators of energy. Double pane windows are better insulators due to the layer of air in between the glass panes. Triple pane windows are even better at insulating but incur additional costs. A single pane window typically has R-value of 1, Double pane is R-4 and triple pane is R-8.
These are major household appliances like refrigerator, washer, dishwasher etc. that are certified by the federal Govt. as energy efficient. It is advisable to replace appliances at end of life with energy star versions.