Anyone else find their garden office uses way more power in winter than they expected?

Definitely caught me off guard first winter with mine. I'd done all the calculations based on summer usage and completely underestimated how much the heating would pull. Running a small panel heater even on the lowest setting just hammers the battery bank compared to what I'm used to with the narrowboat setup where I'm more disciplined about it.

The other thing nobody really warned me about was the lighting load. Obviously the days are so short that you're running LED strips and desk lighting for hours more than in summer — sounds trivial but it stacks up over a full working day.

A few things that helped me get on top of it:

• Adding a Victron SmartShunt so I could actually see what was happening in real time rather than guessing
• Switching to a proper oil-filled radiator on a timer rather than the panel heater running constantly
• Better insulation around the door frame — embarrassingly simple fix that made a noticeable difference

Still running a fairly modest system — 400W of panels and a Fogstar 200Ah lithium — and honestly winter is a struggle on the grey days. I'm seriously considering adding another panel or a small wind turbine to compensate for the rubbish solar yield November through February.

Curious whether anyone here has found a heating solution that doesn't absolutely destroy their daily budget? Also interested if anyone's tried those infrared wall panels — seen mixed reviews but they look promising on paper.

@AlexJones this catches nearly everyone out — heating loads are brutal compared to everything else in the setup.

The other factor people miss is reduced solar harvest. In winter you're not just consuming more, you're generating significantly less. A 400W panel in June might average 2kWh/day; come December in the UK you're lucky to see 600Wh on a good day, and sometimes nothing useful for days on end.

For van conversion I learned this the hard way — panel heaters are essentially off-grid killers unless you've got grid hookup or a serious battery bank. My Victron BMV-712 showing the brutal truth of 80Ah consumed before noon was a wake-up call.

For a garden office with grid access, a heat pump or infrared panel rather than a resistive element makes a massive difference to the consumption figures. What's your current battery capacity if you're running any storage?

@AlexJones the heating calculation catches people out every single time. The real problem isn't just wattage — it's duty cycle. A 2kW panel heater running 40% of the time in November is 800W average draw, but come January with a poorly insulated structure it'll be cycling 70-80%. That's before you factor in reduced solar yield.

In my static caravan setup I switched from resistive heating to a small 240V ASHP unit — dramatically better efficiency. Victron MPPT logging showed the difference immediately.

Proper insulation is worth doing before you throw battery capacity at the problem. Spraying the cavity or adding PIR board to walls pays back faster than another Fogstar battery bank.

What's the actual insulation spec on your office? That determines whether you're fighting a losing battle or just need to right-size the storage.

Yeah this absolutely got me too. My shepherd's hut is the same deal — thought I'd sized the battery nicely then December hit and I was scratching my head wondering where all the juice was going.

Worst combo is heating plus shorter days meaning your panels are doing basically nothing. I'm running Fogstar lithium now which helps because you're actually using the full capacity, but it doesn't magic away the underlying problem.

Honestly the only thing that properly helped was adding a small woodburner for the main heat load and keeping electric just for top-up. Takes the pressure off the system massively. Might not suit a garden office setup depending on regs but worth looking into if you can swing it.

@AlexJones exactly the same situation with my cabin. The thing that really caught me out wasn't just the heating load itself — it was the combination of heating running longer and the solar input being a fraction of what it is in summer. You're fighting both ends simultaneously.

I've got Victron kit monitoring everything and looking back at my data, December consumption was nearly 3x my August average. Same devices, same usage patterns, just the heater doing its thing on dark days.

Have you looked at whether your insulation is doing what it should? I found improving that made more difference than adding panels — the heater simply cycles less frequently when the fabric of the building is decent.

Narrowboat winters taught me the hard way: your worst-case load × worst-case hours × worst-case solar days is the only calculation that matters, and even then December will laugh at you.

Swap that panel heater for an oil-filled rad with a proper thermostat — they cycle on/off rather than running flat-out, which makes a massive difference to your actual daily consumption vs the nameplate wattage horror show.

Also worth checking if your Victron (or whatever you're running) has consumption logging — comparing a July day to a January day is genuinely eye-opening and helps you work out where the watts are actually going rather than guessing.