A ratio used to determine whether a project that aims to save money in the future is worth doing. The ratio compares the investment that is put in now with the amount of savings from the project.

SIR takes the total energy savings over the lifetime of the improvement (Present Value) divided by the upfront cost of the investment. This calculation may or may not include increases in energy prices or inflation rates. See lifetime improvement charts below.

This number is similar to the interest rate for a savings account, except you are comparing it to the investment in energy savings. By comparing the MIRR to the interest rate on the loan, you can determine if the investment makes sense.

Snugg Pro uses the NREL (National Residential Efficiency Measures Database) for the default costing of each recommendation.

Factors like climate, construction, home features, local economy, contractor pricing, and geographic location affect the magnitude of the cost range.

The database is not intended to provide costs for specific projects because of the wide variability in costs driven by the factors mentioned above. Rather, it is meant to provide guidance regarding the range of measures and associated costs generally available in the marketplace.

Always review and/or edit the default cost on the refine screen and determine if it matches with what you are actually recommending.

A contiguous air volume within a building that contains a combustion appliance such as furnaces, boilers, and water heaters; the zone may include, but is not limited to, a mechanical closet, mechanical room, or the main body of a house, as applicable.

The measure of the energy efficiency of room air conditioners: cooling capacity in Btu/hr dtided by the watts consumed at a specific outdoor temperature.

The measure of efficiency for a variety of appliances. For water heaters, the energy factor is based on three factors: 1) the recovery efficiency, or how efficiently the heat from the energy source is transferred to the water; 2) stand-by losses, or the percentage of heat lost per hour from the stored water compared to the content of the water: and 3) cycling losses. For dishwashers, the energy factor is the number of cycles per kWh of input power. For clothes washers, the energy factor is the cubic foot capacity per kWh of input power per cycle. For clothes dryers, the energy factor is the number of pounds of clothes dried per kWh of power consumed.

The measure of seasonal efficiency of a heat pump operating in the heating mode. It takes into account the variations in temperature that can occur within a season and is the average number of Btu of heat delivered for every watt-hour of electricity used.

A factor of how susceptible your house is to wind, influenced by weather patterns, location, and the number of floors in the home. Used in the calculation of NACH.

The number of times in one hour the entire volume of air inside the building leaks to the outside naturally.

A measure of the capacity of a material to resist heat transfer. The R-Value is the reciprocal of the conductivity of a material (U-Value). The larger the R-Value of a material, the greater its insulating properties.

A measure of seasonal or annual efficiency of a central air conditioner or air conditioning heat pump. It takes into account the variations in temperature that can occur within a season and is the average number of Btu of cooling delivered for every watt-hour of electricity used by the heat pump over a cooling season.