lewster |
05-15-2011 09:53 AM |
In the world of larger motor homes, you NEVER see a roof A/C unit with a heat strip any more. I would guess they went out of 'fashion' around Y2K or so. I had a '98 Monaco Dynasty 40' diesel MoHo that had 2 roof units with heat strips, and they were all but ineffective when it was cold. They would take a little of the chill out of the air, but were all but worthless as a heat source. Actually, I preferred to use the small 120VAC powered heat cubes to the furnace, which was very noisy and had a severe drying effect to the heated air. That's easy to do in a MoHo with a 7500 watt on-board diesel generator.:brows:
Heat pumps however, with their thermostatic control feature, rival a furnace down to about 40*F. After that, you really need the furnace or other heating source like an Aqua-Hot hydronic heating system. And remember, the compressor of a roof heat pump unit doesn't really know whether it is heating or cooling the RV, it just compresses the refrigerant and the reversing valve handles the job of directing the flow of the refrigerant which determines the unit's operation: A/C or heat pump. Of course, it's a little difficult to run a roof unit as a heat pump while off-grid unless you have a large enough generator. This is where the furnace becomes most useful.
In A/C mode, the inner coil acts as the evaporator and becomes extremely cold, so the air passing over it is also cold when directed into the RV. In heat pump mode, the inner coil becomes the condenser and gets very warm, thus sending warmed air into the RV. All the while, the compressor is doing the exact same job; compressing the refrigerant.
So yes, a heat pump will run longer that a strict A/C unit and might possibly effect it's operational life. But with these units failing in as little as 6 months, I would not be taking any bets on their longevity for either type of unit. The best bet is to sigh up for the manufacturer's extended warranties that are offered on new units. For a fee of about $100 or so, you can buy full parts/labor coverage for your new unit that will extend the original warranty out to a total of 4-5 years. The manufacturers offer this directly to the owner, so there is no middle man to file a claim thru.:D
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