March 2024 Can heat pumps be a viable alternative form of heating?
With boat owners often having a close connection with the natural world, it isn’t surprising to learn that many are looking to do their bit to decarbonise the waterways.
AN increasing number of waterway users are looking to use HVO fuel or to fit more solar panels to reduce their need to run generators or engines. And with councils now being able to prosecute boat owners who burn wood and coal in their stoves, thoughts are undoubtedly moving towards boat heating and what alternatives are available.
We’ve all seen the publicity surrounding air source heat pumps for the home, which are seen as the natural alternative to gas boilers for heating our homes. So the question is: can a similar technology be used to heat a boat, and if so, does anyone offer such a device that works? I was asked these questions a number of times while I was carrying out research for this article by both boaters and those associated with the waterways. As a result, I started looking into the subject.
Tackling the obvious issues
One company I contacted was Kensa Heat Pumps based in Cornwall, which supplied one of its 3kW Shoebox heat pumps for installation in a boat called Tulak. The heat pump itself is said to be one of the smallest on the market, which was undoubtedly a major consideration. The company was founded in 1999 by a pair of former marine engineers, and its first heat pump was designed to be installed on board a boat using seawater as the energy source. The boat was built by Elton Moss Boatbuilders in Cheshire for Nick Clack and Ali Roberts, who wanted the boat to be as environmentally friendly as possible. However, despite the heat pump’s name, finding a location for a unit measuring 530H x 475W x 370L could prove to be a challenge on a narrowboat, given that Tulak is 12ft wide x 65ft long and has three bedrooms. But at the suggestion of a fellow Towpath Talk contributor, I did find one of Kensa’s Shoebox heat pumps on one of the smallest narrowboats you are likely to find. More of that later.
One of the biggest names in boat heating has to be Eberspacher. They don’t currently offer a heat pump option for boat heating partly because of an issue heard from some boat builders who are concerned about the water supply to the pump and that blockages could pose a problem. However, with water-sourced heat pumps using a skin tank and not using a feed of water from the canal or river, this shouldn’t be seen as a reason not to consider one. Who knows, maybe we will see a heat pump from Eberspacher in the future.
It was a similar situation with Fischer Panda, who, when asked about other options for boat heating, offered a range of air-con units that it felt would be compact enough to fit on the roof of a narrowboat without causing any air draught problems. Chris Fower, Fischer Panda UK’s sales and marketing director, told
us: “Rooftop air con is a simple refit option. We use them a lot on vehicles with no feedback on efficiency issues when heating. Finding space is obviously dependent on roof space available, but these units aren’t very big.” He added that these are “really simple to fit, have no water cooling issues, and are space-saving”. But with the roofs of narrowboats being used for solar panels and many other things, plus with the roof being far from flat, I’m not sure the air-con option would be ideal, but I’m sure Fischer Panda will probably be able to overcome the contour issue.
A valuable resource?
There are few examples of narrowboats fitted with anything other than conventional heating. That is until you speak to Alasdair Kirkpatrick, proprietor of Beacon Park Boats, the gentleman suggested by my fellow Towpath Talk contributor Jonathan Mosse. Beacon Park Boats is a family business that has been offering narrowboat holidays on the Monmouthshire and Brecon Canal since 2001. All of its boats are bespoke, including its fleet of day boats, which are all electric. When I asked about the use of heat pumps in narrowboats, Alasdair suggested looking at the company’s boat, Robin, a fully electric boat which forms part of Beacon Park Boats’ commitment to tackle climate change.
This almost 27ft long, two-berth boat is beautifully fitted out with an induction hob and with hot water and heating generated by a water source heat pump. In Alasdair’s opinion: “She is truly revolutionary.” Robin is the smallest boat in the fleet to be equipped with a small amount of living space. It is equipped with solar panels and two battery banks providing 5kW of electricity. These banks can be swapped over if needed, but dependent on the user’s power consumption, this isn’t always necessary.
Robin was designed with a heat pump in mind, so space was made available below decks for one of Kensa’s Shoebox units that produces warm air via a vent in the cabin as well as a tank of hot water. Alasdair said that the unit is capable of 50C. One of the questions he’s often asked is: “What if the canal freezes?” As he pointed out: “The canal never fully freezes to the bottom, and as long as there is a 1C temperature difference, a heat pump will work.”
In fact, in Alasdair’s opinion: “CRT is sitting on a valuable resource”. He feels that the heat energy contained in the canal system could and should be used to heat homes along the waterways system, a consideration he has discussed with CRT in the past.
Alasdair is a pioneer of low-carbon energy and has guided the company in its transition to using the sizeable solar array on the roof of its workshops to power even the most power-hungry, three-phase equipment in the woodwork shop. Waste wood from this shop is used to feed the heating system and biomass generator on site, and even the wood chip waste is converted into briquettes for use in the hire fleet stoves.
It’s good to see Alasdair and the team at Beacon Park Boats continually looking for ways to reduce the carbon footprint of the business, something I feel businesses in all sectors should be doing. As for heat pumps, there isn’t a lot of choice for the boating community at the moment, but I’ve no doubt this will change.
As for installing one in your boat, the main issue would seem to be the need for a skin tank for the pump to use. If this can be done as part of a major refit, then it could be worth consideration, and if you are having a new build, you should definitely look into it and talk to your boat’s builder. Heat pumps are more expensive than a conventional system, so it would seem to come down to how much value you put on reducing your carbon footprint.