Choosing the Right Heater for: Cruisers


Cruisers typically have more equipment in the engine compartment that needs protection. In addition to the main engine(s), there may be a generator, fresh water plumbing, a hot water heater, and air conditioning lines that carry water.

There are also likely through-hull connections with strainers that take in water for these systems. With so many designs of boats on the market, we can’t offer specific instructions for each situation, but here are some general guidelines that should help you make an educated decision.


Cruisers below 28 feet

Cruisers below 28 feet in length are typically powered by a single i/o engine. Well equipped models may have a generator, air conditioning and a hot water heater with the generator and water heater typically being located in the engine compartment.


Depending on how large your particular engine compartment is, a single Medium (450 watt) or Large (600 Watt) heater should keep things warm enough to prevent freezing in all but the most harsh winter conditions.

Cruisers above 28 feet

Cruisers above 28 feet in length typically have twin engines and generators, as well as water heaters and one or more air conditioners. Boats that are powered by inboard engines rather than I/O packages will have sea strainers made of glass or plastic attached to the engine intakes.


While boats in this class with relatively small engine spaces can get away with a Medium (450 watt) heater, a single Large (600 watt) Xtreme Heater is recommended as a starting point for this size boat.

Boats of this size tend to have larger vents that will work like a chimney, siphoning off heat, if left uncovered. As cruisers get larger, the beam (width) of the boat grows larger. Boats with a beam over 13 feet would benefit from two heat sources. Rather than a single Large (600 watt) heater, we would recommend twin Medium (450 Watt) heaters for complete protection.


These guidelines for heater selection are intended to help you make an informed choice regarding the size, number and placement of your Xtreme Engine Compartment Heater(s).  The infinite number of variables involved, including boat and engine compartment configuration, storage location, local weather conditions or extreme weather events make it impossible for us to make definitive recommendations for specific boats in specific locations.  Our testimonials page is a great place to see boat and heater combinations that our customers have found effective.



I’m impressed with your design of the Xtreme (450w)

It’s January in Maryland and my wife and I just took the boat to Baltimore’s Inner Harbor for the weekend. I think we were the only ones out except for the commercial traffic.

What a treat!