Temperature Control Overview
Think of your van as a pocket of air you’re trying to maintain—warm when it’s cold outside, cool when the sun is beating down. Every climate control decision you make, from insulation to heaters to AC, is about managing how quickly heat enters or escapes that pocket.
One common way to measure a material’s resistance to heat transfer is R-value. In simple terms, the higher the R-value, the better the material slows the movement of heat through it. But here’s the catch: even the highest R-value won’t help much if you have gaps in the shell. Missing insulation, unsealed seams, or poorly covered windows can undo the best materials and equipment.
Your climate control isn’t just a collection of gadgets. It’s an interconnected set of parts:
Insulation slows heat transfer.
Ventilation moves air to control moisture and temperature.
Heating & cooling systems adjust the temperature inside the air pocket.
Seals & covers protect the boundaries of the system.
Advancements in technology have made climate control far more approachable for the average full-build customer. More efficient heaters, 12V air conditioners, and improved ventilation products have pushed comfort into territory that used to be unrealistic in off-grid vans.
Still—it’s a van, not a house. No matter how dialed your system is, you’re still camping. Embracing that reality will help you strike the right balance between investment, energy use, and comfort.
Fans & Ventilation
Cheap, efficient, and essential—fans keep air moving, smells down, and moisture under control. We’d argue every camper van needs some form of ventilation. With the right setup, you can move enough air through a small space to make it surprisingly comfortable even in summer heat.
Two roof-mounted fans, positioned to push and pull air, can cool the van faster than you might expect. Another proven option is pairing a vented window near the bed with a roof-mounted exhaust fan—ideal for warm summer nights.
Fan Options We Use Regularly
MaxxAir
7500K – full-featured model with remote and reversible airflow
MaxxFan Mini – compact option for combining airflow and illumination. The lack of speed control makes this thing somewhat noisy, but it’s great for exhausting the area above your stove and since it doesn’t open, you can put solar panels over the top of it.
Circular fans – smaller footprint for specific spaces like a shower stall
Sirocco Fan – great for directed airflow, especially by the bed. Adjustable, quiet, and efficient.
Windows with built-in fans – newer to the market. We haven’t installed them yet, but the concept of integrated airflow at a window could be really nice for those warmer nights.
Accessories
Van Essential Insulated Fan Cover – keeps heat in during the winter and blocks sun in the summer, helping your fan opening work like a true four-season feature.
Ventilation isn’t just about comfort—it protects your build from moisture damage, prevents stale air, and makes your time inside the van far more enjoyable year-round.
Heaters
A good heating system turns a camper van into a true four-season vehicle. Our shop exclusively sells and installs Espar/Eberspächer heaters, but much of what follows applies no matter which brand you choose.
Air Heaters
Often installed under the passenger seat, air heaters are a reliable and efficient way to keep your van warm in cold weather.
Fuel type: In our experience, diesel tends to be a bit more reliable than gasoline, but modern gas models (when installed properly—see forum link) perform well too.
Models we use:
D2L (diesel) / B2L (gas) – compact, efficient, ideal for smaller vans (144", 148", 136").
D4L (diesel) / B4L (gas) – higher output, better for larger vans.
Pro tip: Don’t oversize your heater—large units in small vans will short-cycle, leading to carbon buildup and more frequent service/errors.
Maintenance tip: Run the heater on high for 10–20 minutes each morning before leaving camp to burn off carbon deposits and extend service intervals.
We source all our air heaters from EsparParts.com for product quality and warranty support.
Hydronic Heater Options
Rixen’s Enterprises – Premium Kits
When it comes to complete hydronic setups, Rixen’s Enterprises makes what we believe is the best all-in-one solution on the market. Their systems come with advanced controls that outshine anything else we’ve seen and are highly customizable.
Some standout features of Rixen’s kits include:
Vehicle coolant integration – capture heat from your engine to warm your water system.
Engine pre-heat – warm your engine on cold mornings before you start driving.
Heated flooring – add radiant floor heating for maximum comfort.
Electric heating element – run the system combustion-free when you’re plugged into shore power.
This is, without question, the most expensive option—but if you want a top-of-the-line heating and hot water setup with flexibility and superior controls, Rixen’s is the way to go.
Esparparts.com – Mid-Range Kits
For those looking for a more budget-friendly option without sacrificing quality, esparparts.com offers comparable kits. They’re the main authorized Espar distributor in North America and have decades of experience selling and servicing these systems. While the feature set isn’t as comprehensive as Rixen’s, these kits are solid, reliable, and often a better fit for builds where cost is a bigger factor.
Heatso – Budget Kits
At the more affordable end, Heatso sells genuine Espar heater kits at lower prices. The catch: they’re not an authorized Espar/Eberspächer distributor. That doesn’t mean the products aren’t real—just that warranty support and service can be more complicated.
We actually run one of these kits in our rental van, and it performs great. That said, if you’re not comfortable doing your own troubleshooting or repairs, it may be worth spending the extra money on a kit that’s backed by manufacturer support.
Electric Heaters
Generally inefficient for off-grid use—battery drain is significant.
Electric blankets are manageable, but space heaters only make sense when plugged into shore power.
For mobile living, combustion heat is king.
Fuel Tank Tapping
For heaters running at altitude, a proper fuel tank tap is essential.
Transit – Rixen video, Transit forum post
Sprinter – most Sprinters have a factory fuel port (video explainer). If your van doesn’t have this option you can tap the fuel sending unit instead (Fuel tap install tutorial)
Promaster – Installing Espar B4L
A well-chosen heater, properly sized for your van and climate, is one of the biggest upgrades you can make for year-round comfort.
Air Conditioning
Air conditioning in a camper van isn’t always essential—but in certain use cases, it can make a world of difference. If your travel plans include hot, humid climates or extended time in direct sun, the comfort an AC provides can transform your van from bearable to truly livable.
When AC Makes Sense
Seasonal travel to hot regions – keeps the van comfortable during heat waves or summer road trips.
Pets on board – provides a safe, climate-controlled space when parked.
Working or living full-time in the van – allows productive indoor time even on hot days.
Power Considerations
With a robust solar system and sufficient battery capacity, you can use AC strategically—cooling the van during peak heat while keeping battery reserves reasonably full.
Ongoing, all-day use is difficult without shore power, a large battery bank, or a generator. You can run air conditioners for hours on end with larger modern battery systems, but anything beyond 1-2 days of heavy usage will require a plan for recharging your system.
Technology Improvements
12V, 24v, and 48v AC systems – dramatically more efficient than previous-generation AC units, allowing longer use on battery power alone. These units often aren’t as powerful as their 120V counterparts, but they do cool effectively and can allow you to stay off grid longer while still keeping cool.
Check out this test Upfitters Wholesale did on some of the most recent DC powered air conditioner options
In short, AC is still a luxury in van life, but it’s becoming a more realistic option thanks to efficiency improvements, better battery systems, and compact designs. For the right traveler, it can be the difference between enduring the heat and enjoying the journey.
Insulation
If you think your climate control systems—fans, heaters, or even AC—will keep your van comfortable without factoring in insulation, think again. Heaters and air conditioners installed in a van without insulation are fighting a losing battle.
A well-insulated van helps:
Reduce system strain – keeps heaters and AC units from running at full blast constantly.
Maintain interior temperature – slows the rate of heat transfer in both directions.
Lower energy use – means fewer amps pulled from your batteries over time.
Improve comfort – creates a more consistent and quiet living environment.
In most vans we skip insulating the floor—adding insulation here increases both cost and height, and the benefits are minimal compared to the rest of the van. We’ve done it, but for most of our van builds it isn’t a priority. If you do decide to insulate the floor, we strongly recommend framing the insulation (example here) so that your floor doesn’t flex and move as you walk over it. We’ve seen a lot of vans with foam board insulation below a subfloor and this almost always results in an unstable floor that will prematirely degrade your finish flooring material.
Approach
Full coverage behind walls & in cavities – reduces heat transfer and helps with sound dampening.
Skip the floor – (in most cases!) keeps build height comfortable and saves budget for more effective areas.
Seal gaps – prevents drafts and stops heat or cold from sneaking in through small openings.
Material Options
For shop builds, we typically install precut insulation kits. They’re faster to work with and reduce labor time—a big deal when hourly shop rates add up. If you want to add R value beyond that, we have used Lizard skin on the sheet metal and reflective insulation on the back of wall panels, but we always use Thinsulate, wool, or an equivalent kit as the main insulation layer behind the walls. For most vans, a solid layer of thinsulate/wool will be sufficient.
For DIY builders looking to save money, buying bulk insulation and cutting it yourself is the way to go. Popular materials include:
Thinsulate – lightweight, mold-resistant, easy to work with.
Havelock Wool – natural fiber option with good thermal and acoustic properties.
The key is to be thorough. Well-installed insulation doesn’t just keep your van warmer in the winter and cooler in the summer—it makes it quieter, more efficient, and more enjoyable to spend time in no matter where the road takes you. Want another take on van insulation? Flatline Van Co has put together a good explainer guide as well.
Other Useful Gear
Not every comfort item in a van needs to be hardwired or permanently installed. Some of the simplest additions can make the biggest difference in how cozy and functional your space feels, especially when temperatures swing.
Comfort & Warmth
Heated blanket – efficient for spot heating, especially when plugged into shore power or running a generator.
Mr. Buddy heater – portable propane option for quick bursts of heat (always use with proper ventilation and proper safety precautions)
Hot water bottle – old-school but effective; tuck it into your sleeping bag before bed for hours of warmth.
Rumpl insulated blanket – high-quality puffy fill for packability and warmth.
Windows & Ventilation
Vented windows – improve airflow and work well in combination with roof fans for cooling.
Insulated window covers – reduce heat loss in winter and heat gain in summer while improving privacy. We like the Van Essential product line (they even have reflective options available)
These smaller items might not be the stars of your build, but they’re often the reason you sleep better, stay warmer, and enjoy the road a little more.
