Energy Efficiency FAQ

Basics

Home energy efficiency is a series of steps and lifestyle changes that allows a household to accomplish needed tasks while using less energy, thereby resulting in a reduced utility bill and lower carbon footprint.

Usually it can be broken down into three basic approaches: 1. Simple lifestyle changes, 2. Light efficiency measures, and 3. Heavy efficiency measures. The steps become progressively more costly and complicated, but the resulting energy savings also increase.

All types of energy, be it electricity, natural gas, gasoline, etc. can be saved by executing various 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 similarly sized gasoline vehicles.

For this, you need to have some idea about how much energy a particular device or task is consuming in the home. Then you can more effectively assess before and after energy consumption patterns to arrive at a conclusion. For this type of investigation, one can sometimes find approximate estimates online, but to obtain greater accuracy, it is often useful to use an energy-measuring device like a “Kill-A-Watt” meter. A whole-house energy audit performed by professionals also comes in handy. In general, space conditioning and water heating consume the majority of energy inside a household and provide the greatest opportunity for energy savings.

This means the most value for the money is generally obtained when doing the initial steps of saving energy. After the initial easy and cheap steps are taken, saving additional energy gets progressively more difficult and the payback period of the extra investment on efficiency often keeps on increasing.

Economics

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 power strip is an intelligent multi-point electrical outlet that has some extra electronics to create primary and secondary outlets. It monitors the primary outlet continuously and when the appliance connected to it is switched off, it completely cuts off power from the secondary outlets, thus removing the power leaching due to stand-by or idle power. For example, in the case of a computer system, the desktop CPU can be connected to the primary outlet and all peripherals and monitors to the secondary outlets. This stand-by power leaching is usually small, but it adds 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 a year.

Using measures such as LED bulbs, smart power strips, weather stripping, and smart thermostats, a household can sometimes save as much as $20-25 monthly on its utility bill. Since these measures will almost always cost well under $500, the payback is swift and the effort needed is also minor.

The cost of weatherizing a home varies enormously, depending on the age of the home, the climate, local labor rates, etc.  Measures like double-pane windows and attic/wall/floor insulation can often cost many thousands of dollars in material and labor. However, such measures can save about $500 – $1000 (or more) in space conditioning costs in a year, so simple payback periods can often be in an acceptable range.  The federal tax credit (which is available during 2021), along with various state, local, and utility incentives can help to improve the payback.

This depends on the size of the house and the number of windows, but the costs are often over ten thousand dollar and it can be a major decision from a homeowner.

Steps to use

This is a step that anyone can take without spending any money. It represents a different way of doing things that leads to energy savings.

Some examples of measures that conserve energy but do not incur any appreciable costs include: 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.

These are steps that incur relatively minor costs and effort but generally result in significant energy savings over the course of a year.  Some examples are switching bulbs to LEDs, installing a smart thermostat, using smart power strips, weather stripping and caulking, and installing low-flow faucet aerators and shower heads.

A smart thermostat automatically programs itself by sensing the schedule of the home’s occupants and optimizing the heating/cooling energy needed for the household. It is also usually Wi-Fi connected, controllable from a smartphone-based app, and gives the consumer feedback about his/her heating and cooling energy use. Typically space conditioning consumes 40-50% of a household’s energy, 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 that would otherwise be consumed by the water heater.  Devices that meet the US Environmental Protection Agency’s efficiency and performance criteria are provided with the “WaterSense” label.  (This is similar to the Energy Star labeling program for energy-consuming devices.)

Weather stripping around leaking doors and windows cuts heating and cooling costs by reducing the amount of conditioned air that leaks out of a house.  This can generally be implemented as a DIY measure, making it especially cost effective.

These steps are more costly and time consuming, but also result in substantial energy savings. Heavy efficiency measures include ceiling, floor and wall insulation, double/triple pane windows, and energy star appliances.

Insulation of the housing envelope reduces the heat loss to and from the interior of the home, much like the principle of an insulating thermos. This in turn reduces the energy needed for space conditioning – not only heating, but also cooling in summer.  Newer houses are typically insulated already, but older homes might have little or no insulation. Insulating the attic is the easiest approach, and is often accomplished by the use of fiberglass batts or spray-in cellulose.  Similarly, exterior walls are often insulated by the installation of fiberglass batts once the siding is removed) or by drilling holes in the walls and injecting cellulose or another insulating material.  In the case of houses with a crawl space, the area underneath the floors can be covered with spray foam insulation. However, houses on concrete slabs have no easy way of insulating the floors.

The R-value measures how effective a thickness of an insulation material is in preventing heat loss – the higher the better. Depending on the region, values in the range of R-40 to R-60 are often recommended for attics.  Values up to R-15 are typically recommended for walls.

Single-pane windows are very poor insulators of energy. Double-pane windows are better insulators due to a layer of gas in between the glass panes. Triple-pane windows are even better at insulating but incur additional costs. A single-pane window typically has an R-value of 1, double-pane is R-4, and triple-pane is R-8.

These are major household appliances like refrigerators, clothes washers, dishwashers, etc. that are certified by the US Environmental Protection Agency as energy efficient. It is advisable to replace appliances reaching the ends of their lives with Energy Star versions.

Incentives

Various entities (utilities, counties, etc.) sometimes offer incentives of various types on light efficiency items like LED bulbs, smart thermostats, smart power strips, etc. Some of these items are even provided for free at times.  Incentives are also often available for heavy efficiency measures, including home appliances.  For example, a federal tax credit is available through the end of 2021 for products such as insulation and efficient windows 2021.  Additionally, various state, local, and utility incentives are also often available.