How I install my boat heaters and how to make them better.

In this video I explain how forced air heaters are commonly installed in boats in these relatively cold climates and how they become better when installed with a fresh air intake.
Summer time temperatures are often just under 20 degrees celsius at night here. Some condensation will occur inside the boat during the night.
You can dry that with a properly installed forced air heater in minutes, even if the temperatures do not necessarily require heating during the night.
An other reason for making a fresh air intake for the heater, is that you can use it for forced ventilation during hot days in case the heater has that option. A dry well ventilated boat is not only more comfortable, but also keeps mold from growing to the boat.
When you plan the warm air ducting in your boat, don't forget to run an extra hose for your foul weather gear closet and for your toilet.

[@MichaelGustavsonArchitect]

Was it more dry with fresh air or with recirculated air? You said it made a big difference, but I couldn't tell in which way it made a big difference.

[@Scramasax]

Oh my bad! I'm glad you brought it up! Definitely better with fresh air, no question. edit: The heater I currently have installed has 3 connections for intake air. The manufacturer actually recommends to use 2 of those for fresh air and 1 for recirculation. That would be the best compromise between comfort vs economy according to them. My installation is comfort biased, so I have connected all 3 to take in fresh air. I could have an option to install a valve, so I can select from where I want the heater to take the air from, but for now I have decided not to install one, as I'm more than happy with this current setup.

[@lorenzom7237]

@@Scramasax Hi, taking the fresh air from outside and heating it, you dramatically drop the fresh air's relative humidity .That way, the new drier air acts like a sponge on the cabin's humidity. I think another way to improve the system further, might be to add a little fan that pushes outboard the dump cold air from the lower part of the cabin.I that way the air leaving the boat would be not the drier warmer air near the deck openings. Thank you for the video!

[@Scramasax]

@@lorenzom7237 Good points. Thank you!

[@ThePiitteri]

Hyvä tietää. Lisää vaan näitä tällaisia videoita. Suomeksi tai englanniksi 👍

[@Scramasax]

Kiitos palautteesta! Näitä tee se itse juttuja tulee aina välillä...

[@jeffwatts4264]

Insulated ducting would be a waste of money when its used in the cabins as the heat only escapes into the boat

[@Scramasax]

@@jeffwatts4264 I agree. I use insulation only in places where I do not want any heat to be transfered to, like for example where the ducting is passing the refridgerator. The wooden vents in the video are only for radiated heat and for air circulation under the bunks.

[@Escapetosea]

Immensely helpful. Thank you.

[@timothyarmstrong5987]

Hello, First class install. Do you run your heater off the batteries and if so how much power is used?

[@Scramasax]

Hi! The power consumption varies from 0,7 to 4,5 Amps depending on how much heating energy is required. During normal summer night temperatures it's running on minimal power =about 1 Amp. This is connected to the house batteries = 480Ah.

[@timothyarmstrong5987]

@@Scramasax Sounds frugal thanks.