Questions About Heating & Ventilation
Index
Port Bezels
Which is More Efficient?
Is the Espar Heater Really That Hot?
Keeping the Boat's Interior Dry
Which Heating System?
Port Bezels (02/2010)
Question: Could you post detailed photos to your website of the wooden bezels you fitted to your ports to accept Plexiglas covers? Did you do the same for your hatches? We are losing the battle against condensation in Florida's current cold snap. Thanks!
Answer: When we were battling condensation during our two winters in arctic Norway, we used plastic sheeting and weather-stripping to kludge a cheap and cheerful double glazing over the ports and hatches. It wasn’t beautiful but it worked quite well.
However, the bezels that we designed and had built to surround Morgan’s Cloud’s custom ports so that we can attach Plexiglas covers to them in the winter, do a much better job and look a lot better too. Now we’re contemplating how to deal with our large custom hatches…
The bezel is shown in its cold weather configuration with the Plexiglas cover installed. In warmer conditions we remove the Plexiglas so that the port can be opened. Phyllis designed and built the curtains which attach with Velcro. They work well and are easy to remove for cleaning.
The plan that the bezels were made
from. Click to load a larger PDF file.
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Which is More Efficient? (12/2009)
Question: Could you please address the fuel consumption of forced-air bus heaters vs. the Refleks? (See this post for a general comparison of the Refleks and Eberspacher heaters.)
Answer: An accurate comparison of fuel consumption and relative efficiency
between the two technologies would require equipment and time we don’t
really have at our disposal. However, since both systems burn with an essentially
clear exhaust, indicating good efficiency, and diesel fuel has a fixed
amount of available heat per unit of volume, I think we can assume that
their base efficiency is very close to identical. But the air bus heaters
lose a lot of heat through their ducting, as much as 20% in a cold bilge,
I’m told, and in addition, more fuel must be burnt—unless the boat is fitted
with a wind generator and the breeze is very steady—to replace the electricity
used by the bus heaters. Bottom line, I would expect the Refleks to be
a clear winner in overall efficiency.
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Is the Espar Heater Really That Hot? (01/2008)
Question: My experience with diesel heat is that it's hard to light, hard to control, it smells and the deck is covered in soot. That was 25 years ago with the stainless steel pot belly stove in [a] Westsail. You rave about the Espar diesel heater. Is the Espar really that good and does it address my previous experience with diesel heat?
Answer: Yes, the Espar (Eberspaecher) really is that good. Keep in mind that we set a very high standard to make it into our Stuff That Works area. If the Espar had the problems you mention, it would not have had a chance. Our Espar D8 has run for about 4000 hours and has never let us down. Very occasionally, as it fires up, we get a slight whiff of diesel but that clears as soon as it completes the ignition cycle.
The key issues are good installation and to make sure you have it serviced at least once every two years. (If you are mechanically inclined and can pry the service manual out of the dealer’s hands, you can learn to do this yourself.) Also, you should make sure you run it regularly (not a problem for us).
On the installation, it is vital that the power cables are heavy enough and that you follow the instructions for the fuel pickup and fuel pump installation to the letter. Mess up in either of these areas and the thing will drive you crazy. Also, see Keeping the Boat's Interior Dry for our comments and photograph on a proper exhaust for an offshore boat.
If you will be far from service help, it is probably worthwhile investing in one of the little black boxes that allow you to read diagnostic codes and reset errors on the Espar, as well as a few spare parts including a glow plug. Also, keep in mind that on the air units the blower motors only last 2000 to 3000 hours. We carry a spare.
Having said all that, if we were to do it again with what we know now and keeping in mind our heavy usage, we would have installed a water, rather than air, circulation unit from Espar or possibly a Refleks from Denmark. The advantage of the Refleks is that it is a much less complex machine than the Espar and uses no electricity (the Espar is a power hog). The advantage of the Espar is automation: Need heat? Flick a switch and you got heat.
The disadvantage with both water circulation solutions is
that they are more complex to install than the air unit we have. Also the
Refleks requires a real chimney, rather than the simple exhaust of the
Espar, and with a water coil to feed the radiators, which we would need
to heat our aft cabin, it is very large.
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Keeping the Boat's Interior Dry (2005)
Question: Is keeping the interior of the boat dry in the midst of prolonged damp, chilly weather, and/or sea spray just a matter of dorade vents, hull insulation and your Espar heater? DO you have success keeping the interior dry or does it inevitably get damp?
Note Morgan's Cloud's beefy dorade, outlined in yellow..
Answer: If you already have a boat, there are some things you can do to at least help the problem:
- Install an extraction blower over the galley. The stove is one of the biggest moisture generators, particularly since a byproduct of burning propane is water vapor. When we wintered over in Norway we installed a second bilge blower and a vent on the suck side of the blower over the stove and routed the blow side out a dorade. This really helped.
- When installing a heating system you have to decide how much outside air to let into the supply side of the furnace. For example, the Espar on Morgan's Cloud is installed in the lazarette right under a large dorade vent. If we close the dorade, the heater just re-circulates the air, which is more efficient than opening the dorade and letting the heater draw cold air in from outside. However, keeping the dorade at least partly open results in a MUCH dryer boat, since we are drawing in dry outside air, heating it—which drops its relative humidity—and forcing moist warm air out through other ventilators. The point being, you have to think about airflow and trade off efficiency against dampness. We found that in Arctic Norway, where we spent two winters, where the air was dry and cold, it was better to keep the dorades pretty much closed, but in London, England it was better to open almost all of them and get rid of the damp. (The winter in London was brutal for dampness, the worst we have ever experienced. In the end we bought a dehumidifier.)
- Our biggest problem on Morgan's Cloud, like most boats, is condensation forming on the hatches and ports. In Norway we covered both with plastic sheeting separated from the metal by bits of adhesive foam; in effect double glazing—not elegant but it worked like a charm. Update, 2007: During the last refit we designed and had built wooden bezels around each port that accept Plexiglas covers, which will do the same thing and are more elegant.
- Make sure you have
a heater that can be run in any weather offshore. I can't tell you
the number of boats we have met, even in the Arctic, that have to cap
off the heater at sea because of worries about burning something on
the chimney or getting water down it. Don't let anyone sell you one
of those 'toy' exhausts
for an Espar that pokes out of the hull of the boat. Ours is on the
aft deck, massively braced to the rails, and three feet high. The result
is that we can run the heater in any weather. (See picture below.)
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Note Morgan's Cloud's massive heater exhaust—outlined in yellow—that we had custom made and well braced to the stern rail.
Which Heating System? (2005)
Question: What do you use for heating on Morgan’s Cloud?
Answer: We have an Espar D8 8KW (I'm not sure of the BTUs). It is one of the bigger ones they make and keeps us toasty in all weathers. One thing I would suggest is not to use the exhaust exit in the hull that they normally specify. In heavy weather this will be very vulnerable to flooding. We had Mike Bowden at Ocean Options, where we bought the heater, fabricate us a 4' high chimney with a 'Charlie Nobel' type top that is braced to the stern rail. With this set up we can use the heater even in very heavy weather, which is, after all, when you want to be toasty below.
If I were doing it again I would install one of the Espar heaters that uses hot water and radiators or heat exchangers. It would be more controllable and it would cut down on all the ducting though it would be more complex to install.
We also have a heater that uses the waste heat from the engine to warm the cabin—essentially free heating with no fuel cost.
See Stuff
That Works for
more information on the Espar.
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