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It’s Wise to Winterize

Originally Published in MotorHome Magazine

For many motorhomers, the term “winterization” means the process of preparing for long-term storage. It’s important that water systems be properly protected against freezing, that batteries are cared for and that chassis maintenance is accomplished before the long winter sleep.

For others, it’s yet another travel season, albeit one that requires special preparation. The idea of having your own personal mobile lodge – a warm, comfortable place to nurse frost-bitten toes between bouts of skiing, snowmobiling, ice fishing, snowboarding, or even sled-dog racing – is mighty appealing. Many folks are now using their motorhomes year-round, so winterization has taken on an additional meaning: that of making your coach more comfortable and enjoyable for wintertime use.

To that end, we’ll deal first with winter travel. Then, for those of you who prefer to wait for springtime before venturing out, we’ll describe how to make sure your coach goes into hibernation properly, so it can come out in good condition.

An important element of increasing comfort during cold-weather camping is reduction of heat loss. On most coaches, windows are the primary source; single-pane glass has very little insulative ability, and the vast expanses of it in a typical motorhome permit a lot of thermal energy to escape.

This “heat hemorrhage” can be short-circuited by specifying double-pane windows as a factory option on a new motorhome, but for current owners, one solution involves installation of aftermarket replacement storm windows. The air gap created by this second glass layer greatly reduces the ability of heat to escape, and can make a big difference in interior comfort. Snap-on storm windows and heat-shrinkable window film work in a similar manner. Do-it-yourself storm-window kits, designed for homes, often can be used in motorhomes and are available at hardware stores. Woven-wood or pleated-vinyl window shades also reduce heat loss, although to a lesser extent.

Ceiling vents are also significant heat-losers; stick-on insulation blankets, available at RV supply stores, can solve this problem. Foam board or aluminized plastic-bubble insulation can be cut to fit most vents. Visually checking behind cabinetry often exposes an amazing number of air gaps and openings where pipes and cables are routed through the floor. Once these draft-generators are discovered, they can be plugged with caulk or urethane-foam sealant, available in hardware stores.

Unfortunately, even with the living quarters maintained at a toasty temperature, other parts of the coach that are isolated from the heat of the furnace may be susceptible to freezing. Leaving cabinet doors and drawers slightly ajar in areas where water lines are routed will help improve circulation of warm air.

It may also be necessary to install an air-venting grate or grille that will improve circulation into unheated areas. Freshwater tanks usually are given at least some protection against freezing either by enclosure within the heated interior of the coach or by heat-ducting of furnace air into basement storage areas where tanks may be located. Basement-located tanks may benefit from board-type insulation applied to compartment doors to reduce heat loss, and from other types of insulation that may be stuffed (fiberglass) or sprayed (urethane foam) into surrounding areas. Basement storage-compartment doors should be airtight. However, the only real freeze protection for under-floor tanks is a furnace heat duct that moves a sufficient volume of air into the compartment.

For best results, the coach should have a small furnace return-air conduit between the holding-tank compartment and the living area; air circulation can be further aided by a small DC-powered muffin fan. Re-channeling furnace air can also be effective for above-floor areas that heat does effectively reach, either by attaching a new smaller-than-normal duct tube to an unused furnace outlet or by teeing a small air tube into an existing duct and routing heated air to the problem area.

Slip-on foam insulation can help reduce the tendency of water to freeze in exposed drainpipes. Heat tapes and blankets can be used to protect the freshwater lines, and heat blankets are made for holding tanks — usable only if 120-volt AC hookups are available. Most heat tapes have built-in thermostats that inhibit operation until the temperature drops to near-freezing. The driver’s area on many front-engine motorhomes has less insulation than the rest of the coach. Although it’s often impractical to effectively correct this problem, some relief can be obtained by installing thicker foam padding (or even a second layer) under the carpeting and by sealing any openings for wires, cables, ducting or hoses. In extremely cold weather, the driver’s area can be closed off with vinyl-backed drapes to reduce cold-air movement into other areas of the motorhome.

Although a well-insulated coach requires less furnace run time and has fewer cold drafts, less condensation is a further benefit. Water condenses on cool, poorly insulated surfaces, gradually reducing the moisture in the air. This can make the breathing air uncomfortably dry, especially when it’s aggravated by heavy use of the furnace. Cooking, showering and other activities tend to raise daytime moisture levels (often enough to make opening a roof vent necessary), but the moisture can quickly drop to unhealthy levels overnight. Adequately insulating the motorhome helps to eliminate this problem by keeping the moisture in the air, where it belongs. Ice can jam door locks, as well as compartment locks.

This can be prevented by applying a graphite-based lubricant to the locks and by regularly spraying a silicone lubricant on the door edges and rubber seals. If all your preparation still “rewards” you with a stuck door or lock, an electric hair dryer or heat gun will usually help you open it. Effective use of additional insulation and sealing, as well as possible improvements in furnace heat distribution, are the keys to successful winter camping when 120-volt AC hookups are available. But for boondocking in cold weather, two additional things are essential: ample battery capacity and an effective recharge method.

Winter nights are long and the power requirements of 12-volt DC lights and furnace are high. Also, batteries are more difficult to recharge during cold weather. Even for motorhomes of modest size that are effectively winter-prepared, two house batteries rated at 105 amp-hours each are the minimum. For larger motorhomes, combined house-battery capacity of 225 to 300 amp-hours is preferable; for example, the use of a pair (or even two banks for large motorhomes) of 6-volt golf-cart batteries. Such batteries are wired in series for 12-volt DC output. Also a bank of three or four 12-volt batteries wired in parallel will provide additional capacity, although paralleling more than two 12-volt batteries is not as effective as 6-volt units that are series-wired.

Battery charging via a motorhome engine’s alternator usually is effective, although impractical while camped, and wintering motorhome owners usually rely on AC generators for battery charging while also operating microwave ovens, televisions and videocassette recorders. Unfortunately, many standard motorhome converters offer inadequate battery-charging capability; in some converters, it’s virtually nonexistent. In such situations, many hours of generator running time create very little battery charging, and often the blame is mistakenly focused on the batteries.

For serious winter usage, the converter’s battery-charging output capability should be at least 20 amps. Most single-output converters have an identification sticker that lists total output. This number means total battery-charging output minus current consumed by appliances. If the converter is a dual-output or linear unit that has one output leg for appliances and another for battery charging, the converter rating may be 40 amps, but the battery-charge rating may be only 5 amps, which is negligible. More effective battery chargers are available in RV supply stores. Many serious winter motorhomers install one or two catalytic heaters, which provide constant heat and do not require 12-volt DC power to operate.

This type of heater reduces furnace running time while also limiting fluctuations in interior temperature as the furnace thermostat cycles on and off. A catalytic heater can make a large difference in comfort on cold evenings. With all the insulation, heating and power-generation bases covered, winter motorhoming can be a very different and exciting experience. The water system in an unoccupied motorhome is quite vulnerable to freeze damage, which can be avoided by draining the entire system or by filling it with nontoxic antifreeze.

When draining the system, it is important to get the water out of all the pipes and tanks and the water heater, since even relatively small amounts can cause damage when frozen. Some coaches are equipped with drain valves for this purpose, and it’s usually possible to retrofit them to most others. Separate hot- and cold-water valves are typically used, and they should be located at the lowest point in the water system. The draining process is also made easier by using a blowout plug that attaches to the city-water inlet. This allows low-pressure compressed air to be pumped into the system to displace any remaining water. If the system is to be protected with antifreeze, it’s advantageous to first install a water-heater bypass kit. This allows the water heater to be drained, thereby eliminating the need to add an additional six or 10 gallons of antifreeze to fill the tank. Also, it’s essential to use only nontoxic antifreeze (available at almost any RV supply store and Camping World) specifically intended for this purpose. Never use automotive antifreeze, even the “environmentally friendly” kind.

Condensation usually isn’t as much of a problem in unoccupied motorhomes, since the interior is typically kept much closer to outdoor temperatures. Cracking the roof vents a little will usually help reduce moisture accumulation, although precautions against rain entry must also be observed. Some owners leave a small 120-volt AC incandescent light bulb burning, on the theory that the heat produced will help drive out moisture. Electric strips and chemical-type dehumidifiers that work on the same principle are also commercially available.

Regardless of whether you’re using or storing the motorhome for the winter, it’s important to avoid neglecting the engine coolant. This involves maintaining an adequate concentration of the proper antifreeze type (see your owner’s manual for specific recommendations), along with replacing the coolant every few years. Weak antifreeze can allow the coolant to freeze, causing leaks or potential engine damage. Old antifreeze encourages corrosion, which can also produce leaks.

Before storing a gas-engine coach for the winter, full chassis-lubrication service should be performed, including changing the oil and filter. Otherwise, acids that accumulate in the oil will have the entire winter during which to corrode engine bearings. It also is desirable to protect the cylinder walls from rust by coating them with oil if the engine will not be started for several months. This can be accomplished with engine-fogging oil sold in marine supply stores in aerosol cans. The oil is sprayed into the engine intake with the engine at idle speed, followed by shutdown for the winter-storage period.

This procedure is not applicable to diesel engines, since the introduction of combustible oil in the air intake will cause the engine to race, possibly leading to over-speed damage.

The fuel system in most motorhomes also needs attention. To minimize moisture accumulation inside the fuel tanks, it’s best to fill each tank immediately prior to storage. A fuel stabilizer should be added to keep the fuel from breaking down and leaving deposits. Both gasoline and diesel stabilizers are available at most auto-parts stores.

Tires should be inflated to normal operating pressure, which should be checked every couple of months to make sure pressure loss has not occurred. Also, since continuous exposure to sunlight or moisture hastens the breakdown of rubber compounds, tires should be protected from the sun. Tires will last longer if a barrier of plastic or plywood is placed between the tire and the ground or pavement.

Finally, don’t forget batteries. When the motorhome converter does not have a “float” or storage-maintenance mode (manufacturer literature will specify), it’s best not to leave the coach plugged into shore power with the converter continually operating. Depending on the converter, this may cause gradual loss of water in the electrolyte. A better practice is to turn on shore power about once a month, or use a small AC battery charger that is capable of tapering the current before overcharge occurs. All terminals should be clean, since a poor connection may prevent one or more batteries from receiving a charge. A regulated solar panel can also be used for the same purpose.

When either of these methods is used, the starting battery can be kept charged by connecting it in parallel with the house batteries. This can be done either temporarily with a jumper wire, or by permanently installing a battery maintainer. All terminals must be clean because a poor connection may prevent one or more batteries from receiving a charge.

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