Practical Insulation

Like most, we seek to keep the cold out and the heat in. Many methods are used. I make no claim that our method is the best, it’s just the one we have adopted.

We were able to quantitatively determine how well our method works recently from the observation of how often the furnace turned on while the outside temp remained constant.

Prior to buttoning up, the furnace was turning on every 14 minutes. Afterwards, the interval was 70 minutes. We did not completely button up until after dark, so while the outside temperature remained constant, 34, we also lost the radiant heat of the sun. 

We put Reflectix in all vents and snap the factory supplied covers in place. The cab windows and the shower skylight are also covered with Reflectix. This slowed the furnace cycle somewhat, but the surprising thing to us was how much insulation the window shades provide. We are always reluctant to lower the shades, but now we know the difference they make.

Linley amplifies:

Saw the item on the Lazy Daze Companion about added insulation (in the windows, etc.) making a big difference in heat loss. The item's conclusion made by noting how often the furnace ran was interesting and, in fact, does indicate a good improvement.

However a much more accurate measure is obtained if the percentage of time the furnace is firing measured instead.  This can be found by measuring both the length of time the furnace flame is burning during each cycle (it makes a racket) and also the length of time between the start of each cycle, and then dividing.  

With the percentage of firing time in hand one can get an estimate of the actual heat loss.  Multiply the percentage of firing time times the number of cycles per hour and then take that times the heat output of the furnace in BTUs per hour. 

There is a problem about here because RV furnaces seem to be rated in BTU's per hour of input (i.e. propane consumption) instead of heat output.  A rough guess is that one gets something like 50% or 60% of the input heat as output inside the coach.

Linley

Cold Weather Camping

A fair number of LD'ers seem to use their rigs in some pretty chilly weather. That being the case, folks have come up with all sorts of ways to stay warm inside when it's cold out there. Beyond comfort, you also want to prevent any damage from frozen water lines and/or tanks. The LD manual includes some cold weather tips, which we'll start with here, followed by suggestions from fellow LD'ers.
- Turn the water heater on.
- Open cupboards slightly under sinks and near the water pump.
- Close all drapes and shades.
- Use the windshield boot.
- Hang a heavy blanket to separate the cab area from the coach (the cab is not insulated as well as the coach).
- Install vent covers. These can be obtained from either the Lazy Daze factory or camping supplies outlets such as Camping World.
-- For the escape hatch, cut a piece of 11/2" to 2" styrofoam to just fit into the opening, then install the cover.
- In pre-2003 models, you can cut pieces of 1" styrofoam to fit inside the frames of the cab-over windows and then install vinyl covers (sold by LD).
- Insulate outer compartment doors. Gluing polyurethane or polystyrene foam insulation panels to the compartment doors and using the foam weather stripping on the inside lip of these doors will eliminate most of the drafts and keep the coach warmer in cold weather.
- Insulate the sofa-slide slot to prevent cold air coming in from the compartment below. Here are complete details.
- Cover windows and vents with Reflextix, which is a soft insulating sheet. Essentially, it is bubble pack (i.e. plastic sheets with encapsulated bubbles) with heavy aluminum foil glued to each face. It easily cuts with scissors.- Use elastrometric sheet insulation on the exterior storage compartments and for noise reduction around the generator and water pump. It is a closed cell-black foam with a tough smooth skin that can handle being installed in areas that get wet and/or abused. Use a spray contact adhesive on both the foam and the surface to which it is being applied.
- Insul-Sheet® 1800 Sheet Insulation is a closed cell foam sheet that is used in the air conditioning industry for wrapping pipes and A/C ducting. It is resilient and a good choice for the inside of storage compartments that receive abuse. It is available at Grainger Supply and Johnstone Supply in 36" X 48" sheets, ½", ¾" and 1" thick. The foam is flexible and easy to work with. Use a contact adhesive to attach it to the inside of storage doors and compartments. I use Insul-Sheet's glue, made for their foam. I will be using Insul-Sheet to wrap the holding tank drain lines when I install the pipe heaters later this year
- Rigid closed cell polyisocyanurate foam is sold in 4' X 8' sheets at your local home center in various thicknesses. It has a higher R-rating than the Insul-Sheet foam but is more fragile and can be dented. Use it in places where it will not be bumped or impacted. It is easy to use and can be cut with a utility knife. I use "Hard-as-nails" (water based formula) adhesive for attaching. I have use this to insulate the tops of the outside storage compartments when there is not any factory insulation. I will be using it to insulate the holding tanks later this year after installing the tank heaters.
- Another big source of heat loss is the entry door and step area. This area is always the coldest spot in our LDs. The doors are poorly insulated and can benefit from adding either a door blanket in cold weather and/or a layer of Plexiglas over the window. Attach the Plexiglas using double-sided tape or plastic "L" shaped mirror mounts.
- The screen door can be turned into a storm door by applying Plexiglas over the screen, using "L" clips. The "L" clips allow you to remove the Plexiglas during warmer weather. Add some foam weather stripping around the door perimeter to complete the job. Covering the screen door with Plexiglas allows you you leave the entry door open, letting in light, while blocking the cold wind. This is a good winter time addition for boondockers.
- The entry step is not insulated and can be improved by gluing layers of polyisocyanurate foam under the step.
- You should also be sure that the door weather-stripping is in good shape and seals well around the door frame. Our new LD door leaks when the wind blows against it. This could be a serious problem in extremely cold weather. A better foam weather stripping will cure this.
- If you normally have hookups in your cold-weather camping adventures you can install black and grey tank heaters, as well as wrap the pipes to the valves with heater tape.

Contributors: Linley Gumm, Larry Wade, LD Manual, WxToad

Revised: 12 Oct 13

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