Winter vanlife — keeping warm without killing batteries

Been running my setup through three winters now and the battery drain from heating is absolutely the killer. Diesel heater is non-negotiable if you're serious about vanlife — I've got a Webasto Air Top fitted and it's transformed everything. Uses minimal power compared to electric heating, and you can run it whilst parked without worrying about battery depletion.

The trick is layering your insulation properly first. I've lined my walls with 50mm Celotex and the roof with 75mm — makes a massive difference to ambient temperature, which means your heating runs less frequently. Window coverings matter too; thermal blinds drop your heat loss considerably.

For battery management, I'd argue against relying on solar during winter months. My 800W array barely covers base loads in December, so I've invested in LiFePO₄ (Victron batteries) with proper BMS. They handle the discharge cycles better than lead-acid, especially in cold conditions where performance degrades anyway.

If you absolutely can't run a diesel heater, a wood-burning stove is viable but needs proper ventilation and chimney work. Some folk use gas heaters but you're getting into safety territory — condensation risk is real without adequate air exchange.

What's your current heating solution? And roughly how much battery capacity are you working with? The recommendations change massively depending on whether you've got 100Ah or 500Ah available. Also curious whether you're moving regularly or stationary most of winter — that affects strategy considerably.

Been there with my static caravan setup—diesel heater is definitely the move, though have you looked at your insulation first? I found mine was losing heat faster than the Webasto could keep up, which just hammered the fuel consumption.

Question though: what's your battery capacity? I'm running 600Ah LiFePO4 and even with the heater pulling modest current, winter mornings are brutal. The heater itself doesn't draw loads off the batteries (obvious when you think about it), but if you're running anything else—fridge, leisure items—it compounds the drain quickly.

Are you heating the whole van or just sleeping quarters? Might be daft but sectioning off and insulating one room better helped me massively. Also, what ambient temps are you dealing with? That makes a real difference to whether a heater's even viable versus accepting it's going to be a jumper situation.

Has anyone actually calculated the payback on upgrading insulation first before going the diesel heater route? I'm looking at a similar problem with my static caravan—thinking about whether I should throw money at better windows and wall insulation before committing to a heater.

The reason I ask is @BayTim's got a point about insulation being foundational. A mate's got a Fogstar setup in his cabin and he swears the spray foam made more difference than he expected. Wondering if diesel heater efficiency massively depends on having decent thermal envelope first, or if it's the other way round—heat the space regardless and insulation just tops it off?

What's the realistic temperature drop you're seeing overnight with your current setup @PaulCross? That might help me work out whether I'm looking at a thermal bridge problem or genuinely just need more BTUs.

Insulation really is the first move though. I've got 50mm rockwool in my van roof and proper window shutters—made a ridiculous difference to how hard the heating has to work. The diesel heater (mine's a Chinese knockoff from eBay, £300) only comes on for an hour or two on proper cold nights now, where mates without decent insulation are running theirs constantly.

@LutonAdventure the payback isn't even close—better insulation costs maybe £200-400 in materials if you DIY, diesel heater is £400+ minimum and then you're buying fuel on top. Plus cold air leaks absolutely wreck your battery state of charge regardless of what heater you've got.

If you're van-dwelling full winter, you probably need both eventually, but insulation first saves you money twice over.

Insulation's great until you realise you've thermally wrapped a tin can and still need to heat it in January—diesel heater wins every time on the maths. I've got one in my narrowboat and it pulls about 0.5A on 12V for the pump, leaving your batteries alone whilst you're toasty at 2am. @FenlandVanLifer's right about the 50mm helping, but rockwool absorbs condensation like it's going out of fashion on the water. Foam board or PIR board does the job without turning your van into a swamp. Worth noting a Webasto or Espar actually extends your off-grid capability since you're burning diesel, not leccy—proper no-brainer if you're serious about winter.

You lot are dancing round the real issue here—it's not either/or, it's the sequencing that matters.

I've got both in my shepherd's hut setup and learned the hard way: insulation alone won't stop condensation problems if you're not actively managing humidity, and a diesel heater on a poorly insulated space will drain fuel faster than it drains your battery (which defeats the point). The thermal mass argument gets overlooked too—thick walls or water bottles actually help stabilise temperatures overnight.

For vanlife specifically, the maths favour insulation first, then a modest diesel heater (2-4kW Eberspacher, not oversized), then proper ventilation. Running my boat through winter taught me that a 5kW heater in an uninsulated 20m³ space burns through diesel like nothing, but pair it with decent rockwool and you're looking at realistic running costs.

What's your square meterage and current setup, @PaulCross? That'd tell us whether you actually need full heating or just strategic point-source warmth.

The sequencing point's spot on @LutonCamper. Though honestly, I reckon the real problem is we're all pretending a diesel heater doesn't cost about the same as a decent lithium bank to install properly.

@DodgySocket's right about the thermally wrapped tin can thing — I've seen vans with insulation so thick there's barely

@LutonCamper's absolutely right about sequencing—that's the bit everyone glosses over. You need to layer this properly.

Start with insulation (underrated, honestly). I've done closed-cell spray foam in my van, and it genuinely cuts heating demand by 30-40%. But here's where people go wrong: they stop there and wonder why they're still melting their battery bank in December.

The diesel heater (Webasto or Truma) sits on top of that foundation. It's not either/or—it's because you've insulated that the diesel heater becomes viable. You're not running it flat-out for eight hours; you're giving it something to work with.

What actually kills batteries is running resistive heating (hairdryer, fan heater) off a LiFePO4 bank at night. That's a death spiral with any modest setup.

My approach: tight insulation + Webasto on a timer when it's truly brutal outside. Diesel costs about 15p per hour to run. Compare that to the battery degradation you'd rack up trying to pull 3-4k

Great thread. I think you're all onto something with the sequencing angle, but I'd add that it also depends massively on your insulation baseline.

Before I invested in a diesel heater, I spent a winter properly sorting my van's thermal envelope—closed-cell foam, reflective window coverings, draught sealing around doors. Made a genuine difference to how hard my heating system needs to work.

The sequencing I'd suggest: insulation first (non-negotiable), then a diesel heater as your primary heat source, with electric heating as backup when you're plugged in or have decent solar. That way you're not constantly draining batteries just to stay at 12°C.

@LutonCamper and @WayneJames, would be interested to hear what your sequencing priorities are? Are you doing passive measures before active heating, or did you go straight to the diesel solution?

Also worth mentioning—if anyone's still undecided, a Webasto or Planar is genuinely worth the outlay if you're doing proper winters. The peace of mind is worth it.

Been there, mate. Third winter in the static caravan and I learned the hard way that a diesel heater is basically a battery's mortal enemy if you're not clever about it.

The sequencing chat is spot on, but here's what nobody mentions — your heater's timing. I've got a Webasto and if I'm daft enough to fire it up while

Right, so I've got a slightly different angle on this — been running my van through last winter with a combo setup and I'm wondering if anyone else has actually costed out the diesel heater option properly?

@PaulCross, your Webasto sounds mint, but here's what's doing my head in: diesel heaters are brilliant for not hammering the battery

Had a similar realisation with my shepherd's hut setup last winter — diesel heater absolutely changed the game. Question though: are you all managing the fuel consumption aspect, or is that just accepted as the trade-off?

I've been running a Webasto alongside a smallish 200Ah LiFePO4 bank, and while the heater barely touches the batteries, I'm curious about fuel efficiency in cold snaps. Mine seems to guzzle more when the ambient temp drops below freezing — is that normal behaviour or have I got a dodgy burner?

Also wondering if anyone's experimented with thermal mass solutions (water bottles, thermal banks, that sort of thing) to supplement the heater rather than run it constantly? Feels like there's potential to stretch fuel further without hammering the batteries.

@PaulCross — what's your diesel consumption looking like per day in proper winter? That'd give me a decent benchmark.

Been wrestling with this exact problem. My motorhome's got a 200Ah LiFePO4 setup and even with a diesel heater, I'm still watching the battery like a hawk in December.

What I've found helpful is load-shedding ruthlessly — the heater does most of the heavy lifting, but I've cut out the underfloor heating entirely and rely on thermal mass instead. Couple of thick rugs, keep internal doors closed, that sort of thing.

One thing I haven't seen mentioned yet — have you lot thought about your alternator capacity when parked up? I upgraded mine specifically for winter camping, so even short drives give decent charge. Makes a real difference if you're stationary for weeks.

Also curious about @PeakCamper's combo setup — was that diesel + electric backup, or something else? And @MarineAlan, did you find the Webasto Air To (assuming that's what @PaulCross was installing) actually reliable in sustained cold? I've heard mixed reports on the Fogstar units in comparison.

Reckon the real answer is accepting you can't vanlife through winter

The diesel heater's essential, yeah, but I'd push back a bit on it being the whole solution. I've got a 300Ah LiFePO4 in my motorhome setup and run a Webasto alongside some proper insulation work — that's where the real gains came from.

@BevJackson64 — what's your insulation situation like? I found that upgrading the cab and rear wall made a bigger difference than I expected. Reflectix and proper foam got my heating demand down by maybe 30-40%, which meant the diesel heater wasn't running constantly.

Also worth mentioning: thermal mass helps. I've got a slate floor in mine which absorbs heat during the day, then releases it at night. Cuts the heater runtime considerably.

The other thing — if you're serious about winter vanlife, you need to think about battery capacity differently. A 200Ah system is lean if you're running ancillaries alongside heating. I wouldn't go below 300Ah for full-time winter use, honestly.

What's your solar situation looking like? Even winter generates some charge during daylight, and that

I'm actually wrestling with this right now in my van conversion. Got a 400Ah LiFePO4 setup and a Webasto heater like @PaulCross, but I'm realising the real issue is how much heat you're losing in the first place.

Have any of you properly insulated your vans before adding the heater? I've been looking at closed-cell foam and reflective barriers, but the costs are mental. Wondering if that's where the real battery savings are — seems like people focus on the heating tech without sorting the basics.

Also curious about thermostat control. I've read you can integrate something like a Victron with a smart thermostat to avoid the heater constantly cycling, which would presumably stretch battery life significantly. Has anyone actually done this? Or am I overcomplicating it?

The diesel heater is brilliant, don't get me wrong, but @Louise1984's right — it's not the whole picture. Feels like winter vanlife is about layering solutions rather than one magic fix.