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Wood Stoves and Fireplaces WOOD - K VALUES - WHAT DOES IT ALL MEAN?
Most people have heard of R-Values, which are used for rating common building materials such as fiberglass insulation and glass. However, many texts which cover stoves and fireplaces use K-Values instead of R-Values. Although the two are somewhat related, there are differences.

R-Value: The higher the R-Value, the better the insulating properties of the subject materials. R-Values are most often used to express the thermal resistance (ability to stop heat flow) of a building wall, ceiling or floor. Because of this, most R-Values are calculated at normal temperatures of approx. 75 F. R-Values are easy to add together so calculating the total R-Value of a wall is simply done by adding the values for the sheetrock, insulation, sheathing and siding.

K-value is a measure of heat conductivity of a particular material. Specifically, it is the measure of the amount of heat, in BTUs per hour, that will be transmitted through one square foot of material that is one inch thick to cause a temperature change of one degree Fahrenheit from one side of the material to the other. The lower the K-value for a material, the better it insulates. If the K-value of the material is known, the R-value per inch can be determined by dividing 1 by the K-value (R-value per inch = 1/K value). The LOWER a K-Value, the better its performance as an insulator.

R or K values have nothing to do with whether a material is flame proof, flame resistant or combustible. Styrofoam, cork, wood and polyester are just some examples of materials which are good insulators but will burn or smoke dangerously when exposed to excess heat.

Technical - For those who desire to calculate their own K or R values, please use the following formulas:

1. R value can be calculated by dividing the thickness by the K value.

For US calculations, we use inches as the unit of measurement.
“In the inch-pound units, thermal resistance is measured in degrees F times square feet of area times hours of time per Btus of heat...
Reduce Your Heating Bills This Winter - Overlooked Sources of Heat Loss in the Home by:
Mark D. Tyrol, P.E., http://www.batticdoor.com

Imagine leaving a window open all winter long—the heat loss, cold drafts and wasted energy! If your home has a folding attic stair, fireplace or clothes dryer, that may be just what is occurring in your home every day.

These often overlooked sources of heat loss and air leakage can cause heat to pour out and the cold outside air to rush in—costing you higher heating bills.

Air leaks are the largest source of heating and cooling loss in the home. Air leaks occur through the small cracks around doors, windows, pipes, etc. Most homeowners are well aware of the benefits caulk and weatherstripping provide to minimize heat loss and cold drafts.

But what can you do about the four largest “holes” in your home—the folding attic stair, the whole house fan, the fireplace and the clothes dryer? Here are some tips and techniques that can easily, quickly and inexpensively seal and insulate these holes.

Attic Stairs

When attic stairs are installed, a large hole (approximately 10 square feet) is created in your ceiling. The ceiling and insulation that were there have to be removed, leaving only a thin, unsealed, sheet of plywood.

Your attic space is ventilated directly to the outdoors. In the winter, the attic space can be very cold, and in the summer it can be very hot. And what is separating your conditioned house from your unconditioned attic? That thin sheet of plywood.

Often a gap can be observed around the perimeter of the door. Try this yourself: at night, turn on the attic light and shut the attic stairway door—do you see any light coming through? These are gaps add up to a large opening where your heated/cooled air leaks out 24 hours a day. This is like leaving a window open all year round.

An easy, low-cost solution to this problem is to add an attic stair cover. An attic stair...
© 1995 Tri-Lane Distributing Ltd. Produced for Tri-Lane and adapted for viewing here by Gulland Associates Inc.

Does heating with wood cause global warming ?

What about local air quality ?

Does wood heating harm the forest ?

Is wood heating safe?

By heating with wood you do not contribute to the greenhouse effect as you would by heating with one of the fossil fuels like oil and gas. When oil and gas are burned, carbon that has been buried within the earth for thousands of years is released in the form of carbon dioxide, a by-product of combustion. The result is an increase in the atmospheric concentration of carbon dioxide, the cause of the greenhouse effect.

Although carbon makes up about half the weight of firewood and is released as carbon dioxide when the wood is burned, it is part of a natural cycle. A tree absorbs carbon dioxide from the air as it grows and uses this carbon to build its structure. When the tree falls and decays in the forest, or is processed into firewood and burned, the carbon is released again to the atmosphere. This cycle can be repeated forever without increasing atmospheric carbon. Heating with wood, therefore, does not contribute to the greenhouse effect. And there’s more good news: when the use of wood for energy displaces the use of fossil fuels, the result is a net reduction in greenhouse gas emissions.

Wood is not an inherently dirty fuel that causes serious air pollution. While it is true that old technology like open fireplaces and simple heaters could not burn the wood completely, the new generation of woodburning appliances produce almost no visible smoke and deliver...
Should Fireplaces be illegal ?

Editors Note: The following article is reprinted (with permission) from Home Energy Magazine, which is an energy publication for professionals. It is somewhat technical, but very readable and accurate. As a member of the Industry for 17 years, I personally think that inefficient, open fireplaces SHOULD be against building codes. A building Inspector would refuse to approve your house if you cut a one square foot hole in the wall and let your heated air escape, but that’s exactly what a fireplace does!