R-value is a measurement of thermal resistance and measures the ability of heat to be able to transfer from one side of something to another side. For instance, if there are insulation applied in the buildings that we are living in, the thickness of the walls of the buildings would increase. When the insulating is effecting and walls are thicker, the rate of heat transfer decrease and the higher resistance of heat flow. The lower ability to heat flow, the more likely we would save energy consumption on heat and save some electric bills. The amount of R-value is depending on not only the climate, but also the type of heating and cooling system the building currently have and also the insulation situation the walls currently have. Based on the location of Pennsylvania, we can determine the zone PA is in and then determine the R-value. Also we can type in the type of gas our houses are using, and the zip code to figure out the R-value you would need for each criteria in the building.

Ceiling R-value	38
Wood Frame Wall R-value	20 or 13+5h
Mass Wall R-value i	13/17
Floor R-value	30g
Basement Wall R-value c	10/13
Slab R-value d, Depth	10, 2 ft
Crawlspace Wall R-value c	10/13
Fenestration U-Factor b	0.35
Skylight U-Factor b	0.60
Glazed fenestration SHGC b, e	NR

R-value=ΔT x area x time ÷ heat loss

After applying insulation, the heating systems may lose 2-5% of the total heat input through insulated surfaces. It is not applicable to eliminate all the heat loss relating insulation, but it is possible to reduce these losses by 10-25%.

For example, for a house in PA using electric furnace for their heating system, the recommended R-value for mass wall is 13 to 17. If we decided to insulate the value for R-13 and using fiber glass batt to insulate the walls.

If the original R-value of the house is 1 since the walls are completely not insulated and made up of wood materials. The thickness of the fiber glass is 3 5/8 inch, and the cost is 20 cents/sq ft. If the area of the wall need to insulate is 30ft x 40ft with the height of the wall of 8ft. And we want the R-value to reach 13.

Then the area of the wall need to insulated is about

( 30ft + 30ft + 40ft +40ft ) x 8ft = 1120 sq ft

1120ft x 20 cents/sq ft=22400 cents = 224 dollars

Now that the R-value for the wall is 13, R-value=ΔT x area x time ÷ heat loss

R-value x Heat loss = ΔT x area x time

Heat loss = ΔT x area x time ÷ R-value

the temperature of today is 30 to 18 F, the room temperature in the house is 71F, the amount of heat loss over 24 hours of time

Heat loss = (71F – 30F) x (30ft x 40ft) x 24hours ÷ 1BTU/(hr x sq ft x F)

= 41F x 1200 sq ft ÷ 1BTU/(hr x sq ft x F) =49,200 kWh

Heat loss = (71F – 18F) x (30ft x 40ft) x 24hours ÷ 1BTU/(hr x sq ft x F)

= 53F x 1200 sq ft ÷ 1BTU/(hr x sq ft x F) =63,600 kWh

so before applying insulation, the house lose heat ranging from 49,200 to 63,600 from the highest to lowest temperature.

After applying the insultation

Heat loss = (71F – 30F) x (30ft x 40ft) x 24hours ÷ 13BTU/(hr x sq ft x F)

= 41F x 1200 sq ft ÷ 13BTU/(hr x sq ft x F) = 3784 kWh

Heat loss = (71F – 18F) x (30ft x 40ft) x 24hours ÷ 13BTU/(hr x sq ft x F)

= 53F x 1200 sq ft ÷ 13BTU/(hr x sq ft x F) =4892 kWh

so after applying insulation, the house lose heat ranging from 3784 to 4892 from the highest to lowest temperature.

The amount of heat being saved ranging from 45,416 to 58,708,

49,200 – 3784 = 45,416 kWh

63,600 – 4892 = 58,708 kWh

That is a plenty of energy being saved!

Considering the gas bills for winter times, proper insulation in cold zones should be more approachable to save some energy, and also consider about the cost of applying as construction it is really economically effective to do so.

 http://energy.gov/energysaver/articles/where-insulate-home

http://energy.gov/energysaver/articles/tips-insulation