the coach up to a comfortable temp in three hours. Everything in the coach was eight below zero; the furniture, the carpet, the cabinets, the ceiling, the kitchen sink. In fact the whole interior of the fifthwheel was one big heat sink. Getting all of this very cold material up to room temp seemed to be a daunting task.
Russ fired up the 35,000 BTU furnace, pulled down the day and night pleated shades, turned on the big white ceiling fan for improved air circulation, and let her rip. Much to Russ' delight, by 11:00 the coach was a balmy 68 degrees. Eight degrees below to sixty-eight degrees above in three hours. Amazing.
The shoppers from warmer states were very glad to be sitting and talking to Russ in a nice comfortable coach rather than an igloo and Russ was totally pleased with the quality of our insulation and the fact that the coach was built to our GS specification for insulation. Quality was paying off, keeping everybody toasty.
Then as an experiment, Russ wanted to see how long the 7 gallons of useable propane (one standard tank) would last in this frigid weather with the thermostat set at 68 degrees. It wasn't until 7:00 a.m. on Thursday morning that the propane finally ran out. The warmest it got over that period of time was seventeen degrees above zero on Wednesday afternoon. If the furnace had run full time, rather than cycling on and off as it did, the propane would have been used up by Sunday night. Talk about good R values!
Just like in a house (or a person), eighty percent of all heat loss and gain is through the roof, so in order to have such good insulation values in the coach, you better have a great roof, and our roof is one of the best.
Also, remember that windows have an R value of "1" - its like having nothing there, so the larger your windows, the less well insulated your coach will be. Therefore, one of the parts of our GS Specification is window size control. We make our windows just big enough to allow for good viewing and ventilation and to let light
 Window coverings designed to keep warm air in. |
Because of this, our window coverings are extremely important for keeping out the hot or cold. Pulling down the day and night pleated shades behind the side cornices creates an excellent air damn that impedes convection currents and drafts. Our window coverings act just like storm windows or thermal pane windows in that they increase the R value of the window opening.
Another way we control the quality of comfort during temperature extremes is to keep the slide-outs down to a minimum size. Long and high slide-outs are easy enough to make, but when they get too big the total outside exposed area of the slide-out may increase to a point where we would have to add a second furnace and/or roof air. None of our customers have told us that a second furnace or roof air is a good idea, and many of our customers are full timers who end up in the western desert in the hot summer or don't get out of Michigan in time to avoid the beginnings of winter.
Size control of slide-outs also helps maintain the beam effect of our sidewall structure over the slide-out space. Long unsupported spans create a tendency for the beam area over the slide-out to twist or deflect under compression or torsional loads.
The goal is to allow our bonded sidewalls, made of one and one half inches of block foam, to do their job and keep the inside toasty warm in the winter and cool in the summer. The bonding process allows us to use the same foam that is in coffee cups. Even though a coffee cup may be only 1/8 of an inch thick, it can make a scalding cup of coffee a handleable commodity. Our GS spec for bonded walls with with block foam gives us fantastic insulation roughly equal to at least four inches of fiberglass bat insulation. RV's built to a less costly specification are often disappointing performers in temperature extremes. As an example, two inch fiberglass bat insulation is normally used by most manufacturers in their hung fiberglass, non-laminated sidewalls or aluminum skin non laminated products.
The standards of our industry require testing data to support R value claims. We are aware of only two RV manufacturers who have paid to have their R values laboratory tested, and both are out of business today. Therefore most of the R values quoted in brochures by RV companies are cooked up by the sales manager or by an ad agency. As they see it, the bigger the numbers, the better.
Very frankly, we haven't paid for R value testing either, because to do so is quite expensive. We will, from time to time, quote R values which are printed on materials that we use, but not the total constructional composite R value. All we can tell you is that our R values are good enough for one tank of propane to keep our 35RK with livingroom and bedroom slide-out at room temperature for four days and four nights of sub zero weather, and at the other end of the spectrum, our roof air blows cold in the Kitchen, Living-room, and Bedroom on hot summer afternoons in the Mohave.
