Hydronic Heating vs all Electric

[SootyCamper]

Weighing the pros/cons of hydronic heating vs going all electric. There are certainly some great perks to the system. If you have experience with these types of systems I'd appreciate your feedback.

Background info: My camper will be spending winters in Northern Alberta so reliable heating is essential. I am heavily considering going all electric as while i'm working the camper will be plugged into free 110v shore power supply(my work place also has showering facilities as well) .

The camper will be running a 48volt system with a 32kwh battery bank (two 16kwh Ruxiu batteries ). This camper will be a fulltime livaboard with residential style 48v mini split heat pump (Mini split ) providing adequate shoulder season heating. If I go all electric I'd utilize Mi Heat 48v floor heating mats (Mi Heat), and a ducted DC air heater (48v Heater 20k btu)

Argument for Hydronic:
Available all in one units from timberline and aqua hot have the benefit of providing hot water on demand aswell as providing cabin heat/floor heat. There are some reliability concerns with these units and they do require maintenance. The heater itself will be housed outside the cabin in a storage box, so only my neighbors will be annoyed by the fuel pump ticking and exhaust blowing

Pros:
- Quiet heating (once floors are heated)
- Less heater cycling
- Dual purpose of cabin heat and hot water
- Availability of engine pre heat (will not be tying into chassis engine coolant for reliability sake, but nice to have the option)
- Ability to reduce battery capacity (will reduce overall weight by 320lbs)

Cons:
- Cost+install is 2x more than electric (rough estimate is $6k USD for heater, $5k for install)
- Reliability concerns( many fittings, pumps, tubes)
- Visible/noisy exhaust
- Reduces interior height

Argument for All electric:
Pros:
- Simple install characteristics, very DIY friendly
- No visible/noisy exhaust = more stealth, less Random citizens thinking the camper is on fire
- minimal impact on interior height
- heat an be "Free" when on shore power
- VERY Cost Effective $1200 for 48v Floor heat + 48v Air heater + thermostats, Additional 48v 16kwh battery is $3300usd = $4500 total

Cons:
- Requires large battery bank (+320lbs to overall build)
- High 48v draw ( forced air at Max 1200 watts, floor pads at max draw 2300watts)
- Will need a electric capable water heater. 240v systems seem to be the most effective which will add complexity + additional inverter.



Open to hearing your insights on this topic. It seems every year there are more and more options coming on the market.

 

[Peter_n_Margaret]

I have had a Webasto hydronic heater in our current vehicle for 8 years.
It has been totally maintenance free for that time. It was DIY installed and cost about 1/3rd of what you quote for the heater. It is plumbed to provide engine pre-heating and when driving, the engine provides the heat.
Even when not required for habitat heating, it provides hot water (via waste engine heat when driving or from the hydronic unit while parked) and we can heat just the bathroom and use it for drying the laundry.
If we have excess solar power, we use it to heat the hot water.
The negatives you quote can all be overcome.

I am currently building another expedition vehicle and it will definitely get another hydronic unit.
Cheers,
Peter
OKA196 motorhome

 

[charlieaarons]

All electric in northern Alberta?
Is this a belated April fool’s joke?
A typical small Webasto hydronic has an output of 5kw of heat; a very cold night (~20C) might consume an average of 1.5-2kw (with ~R12 = 0.44w/sqm-hr-deg K + window & vent losses).
So your 32kwh batteries will be dead in about 24h.
OTOH 1L of diesel has an energy content (for oxidation) of ~10kwh; figure 80% efficiency so 8kwh. So a 200L tank will keep you warm 50x longer than your battery pack.

 

[Cummins_expo]

I think you're biggest challenge will be the ability to have a charging system capable of replenishing your power banks in the winter time. Low light, cloudy, snow potential. We have a rig here with a 15kw 48v system, the owner wanted All electric. Here's what we have observed over the winter.
The cold weather overpowering the self heating feature of the batteries. Or running so long you consume more in self heating then you can top off the next day. In some cases the bms goes into cold protection mode and you get zero. Now to be fair if you were living in the camper you would likely have heat running at all times and be less likely to have a cold battery issue. But I think you would have a similar problem. Running heat 24/7 from a fuel source ( electric) in this case would consume it faster then your ability to fill it back up. Even with a massive solar set up. Unless your building a massive rig with tons of roof available.

 

[Trail Talk]

I've documented our challenges with the hydronics in our camper but your post got me thinking; would I do it again? The answer is "yes" because its so versatile. Positives are that it can supply heat to the cabin, the engine, or both at the same time. And it feeds directly off the fuel tank so available at all times in all conditions. Challenges have been coolant leaks at hose and valve connections. The builder has been diligent about addressing these but it takes time to sort, ours and theirs. Not 100% leak free yet due to the extreme temperature swings we endure but the only risk is a slight loss of coolant and I carry plenty. Right now the main annoyance with our hydronics is increasing noise from the Webasto ThermoTop that wasn't solved by a recent unit-out service. Its telling to know that OEV now offers two separate heaters for engine and cabin with independent coolant circuits.

When we have shore power, I'll use an electric space heater. After switching from AGM to LiFePO4, during our winter outings we did experience several low temperature BMS shutdowns overnight while the cabin thermostat was set to its lowest. Heated battery trays were an effective solution and, going forward, I'll stop using the space heater while the camper is in storage.

BTW, we spent the night in Ft Mac last month on our way to the Ft Chip winter road.

 

[Cummins_expo]

I've documented our challenges with the hydronics in our camper but your post got me thinking; would I do it again? The answer is "yes" because its so versatile. Positives are that it can supply heat to the cabin, the engine, or both at the same time. And it feeds directly off the fuel tank so available at all times in all conditions. Challenges have been coolant leaks at hose and valve connections. The builder has been diligent about addressing these but it takes time to sort, ours and theirs. Not 100% leak free yet due to the extreme temperature swings we endure but the only risk is a slight loss of coolant and I carry plenty. Right now the main annoyance with our hydronics is increasing noise from the Webasto ThermoTop that wasn't solved by a recent unit-out service. Its telling to know that OEV now offers two separate heaters for engine and cabin with independent coolant circuits.

When we have shore power, I'll use an electric space heater. After switching from AGM to LiFePO4, during our winter outings we did experience several low temperature BMS shutdowns overnight while the cabin thermostat was set to its lowest. Heated battery trays were an effective solution and, going forward, I'll stop using the space heater while the camper is in storage.

BTW, we spent the night in Ft Mac last month on our way to the Ft Chip winter road.

View attachment 875581

Great looking rig- Not to hijack the thread, but we have found a marine bilge pump heater to be an effective solution to keep the battery compartment area warm enough to stop BMS cold weather issues. A small 400-watt on at 40* off at 50* consumed less power then the self-heating batteries and more dependable then a heated matt

 

[Trail Talk]

A small 400-watt on at 40* off at 50* consumed less power then the self-heating batteries and more dependable then a heated matt

Is yours 12VDC and what exactly is the amp draw? I'm familiar with the Caframo bilge heater (its their cabin heater we've been using) and its disadvantage for us was a required 120VAC and 3 to 9 amps draw. Our two heated trays take 12V right off the battery and use a combined 2A. They are much slower to reach temperature, like 4-5 days, so its something to turn on when winterizing and off again once spring comes.

 

[KarstenP]

I throw in the Truma Combi, available in Diesel, Gas or Propane. It's a dual use air/water heater which can also be had as Combi E with 110V or 230V (Euro) aux. heater. Very easy to install and reliable. We use them in all our builds from pick up cabins to big truck cabins.

 

[Peter_n_Margaret]

ps...
In Oz we do not get the cold conditions encountered elsewhere.
The new truck that I am currently building will have over 2kW of solar, but the central heating and hot water will still be hydronic diesel (with solar/electric option for hot water).
Neither the current vehicle nor the new build have a shore power connection capability.
Cheers,
Peter
OKA196 motorhome

 

[SootyCamper]

As always @charlieaarons brings one back to reality. The energy density of fossil fuels can't be beat!

@Trail Talk I've followed your northern trips closely! You know my situation perfectly (We actually happened to be in Fort Smith at the same time years ago, I snapped a picture of your truck for my instagram!) The issues you had previously posted about regarding your hydronic system drove me deep into the all electric rabbit hole. I love to hear that OEV is continuing to evolve their products, I was VERY close to purchasing a used X10 from Gonegirlglamping, but the thermal bridging is what swayed me away. Sorry to hear that your webasto is being loud, that can be very annoying especially when trying to enjoy our winter!

I hadnt factored the battery replenishment rate as mentioned by @Cummins_expo . Being tethered to my workplace on my days off for free shorepower isn't desirable. Battery temp won't be too much of an issue as they'll be in the living cabin and kept at room temperature, but i should incorporate direct or even passive indirect heating into the battery cabinet just in case.

@Peter_n_Margaret Great insight, webasto certainly produce some really reliable units. 2kw of solar would be amazing!

@KarstenP Does the combi flood the cabin with air heat when heating the water in summer? Or does it utilize electric for water heating in the summer.

I am still in the deign phase of my build so gathering all this feedback is necessary and greatly appreciated. One can only use Chatgpt for so much

 

[smurf40]

Our 2011 Webasto works nicely and has been more or less trouble free. The actual webasto unit did stop working in South America due to the fan crapping out. We replaced it and it’s been trouble free since. The fuel used (off our 600L main tank) is not noticeable. I would do it again on a new build.

 

[KarstenP]

The nice thing with the Truma is, that you can run water, or heat separetly. If you only want warm water in the summer, you just run the boiler without heat and vice versa. You can even mix electricity and fossil side by side. We usually put a 4kw unit in our well insulated (40mm XPS) units up to 6m for temps down to -30° and add the Webasto as a back up unit for people travelling mostly cold climates. You can even get them in 6kw. In summer times I usually run the water heater in the Truma on electric only.

 

[llamalander]

If you plan to connect to-shore power, why not save $4400 and use a portable electric heater/radiator or 2?

 

[Hegear]

I have an Aquahot, that runs of the gas in my truck. I’ve had it for 3 years now and I am amazed how little fuel it goes through,very efficient. The burner went out on it and was replaced under warranty in the first six months. Other than that it has worked great. I don’t use the electric function very often as it sucks to much power for me via the inverter. But I have used if the vehicle is being stored outside plugged directly into 110.

It’s sounding to me like one of these units might work best for you, expensive but really flexible with ability to use fuel and electricity.

 

[Trail Talk]

I am still in the deign phase of my build so gathering all this feedback is necessary and greatly appreciated. One can only use Chatgpt for so much

Were you at Ft Smith during the man-with-gun lockdown? Interesting about the X10, where exactly did it exhibit thermal bridging? We find frost will build up in our deepest interior storage well and on the aluminum frame of the roof hatch. Starting with a fresh design for northern travel is a great idea to attempt that elusive balance of heat retention and ventilation. Minimal holes in the envelope for example (edit: I see that X10 has a lot of windows). An HRV system like Lunos too. For livability, our U-shaped dinette is awesome, can stretch out in many directions. Having a table that can be positioned many ways, especially out of the way, is also useful. Looking forward to following your progress.