How much climate control do you really need in a skoolie?

[dbsoundman]

I ordered a MaxxAir 5200K today, I'm going to try my darndest to get it installed before our trip to FL at the end of March...

[Rucker]

Originally Posted by dbsoundman

Helpful info, but I’m not trying to live in this thing. Trying to balance between creature comforts and budget. I know we talk a lot on this forum about theory and best practices, but I don’t see a lot of people reporting back on their experiences on the road once they’ve finished building, and that’s what I’m looking for.

Great topic. Scattered here and there in this forum I've seen lots of coping skills for non-A/C buses--park in the shade, boondock in cooler places; be out of the bus during the hottest part of the day--but I already had experience with summer heat during the build phase: no way I could enjoy the build without climate control.

I also rented an RV to get a feel for what climate control is needed on a long trip before we began our build. Here's what I came up with.

Climate Control while driving. I definitely need A/C and heat throughout the bus. I kept the native heater and A/C unit because of that. Many folks strip those out as the first step of the build, after ripping out the seats, and I wonder like you many honestly feel in retrospect that was a good idea. The 'base build' in my opinion should include keeping the native dash and cabin A/C and heating system.

Heat while stationary. I have a diesel heater and a Mr. Buddy (backup or for quick warming). The consensus is definitely include a diesel heater in the build. They're cheap and effective. A Mr. Buddy is also cheap and effective but not recommended for long gigs in the bus, especially in very cold climates due to the condensation issues they can create. So in a pinch, a Mr. Buddy, but otherwise the 'base build' should include the diesel heater.

A/C while stationary I have a mini split (runs on shore power or generator). I can't see being without that mini split because I live in California and will be using the bus in Utah, Nevada, Arizona mostly.

In some climates you can consider a swamp cooler (evaporative cooler). I haven't seen many examples of their use here. Probably because they are such a water hog, but worth noting as an alternative to A/C or a supplement to just plain fans.

Consider air handling needs separate from hot and cold air needs. Venting out the hot air, pulling in cool air, exhausting cooking fumes, providing a cool breeze all are quality of bus life features. I'm guessing that's why so many folks rant about the Maxxair fans. My rig will have two marine exhaust fans that can drop in to a number of configurations. I've not fully set them up yet.

[TaliaDPerkins]

To make sure air is as fresh as I want it to be, I got this.


Broan HRV80S Broan HRV80S 77 CFM Heat Recovery Ventilator with Side Ports

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1



Provides for HVAC energy recovery.

[somewhereinusa]

I may be only a weekend warrior but, SWMBO will not go anywhere without AC and it better be cold enough that I will probably need a winter coat. The radiant floor heat is because I'm an old grouch if my feet aren't warm.

[Rucker]

Originally Posted by TomDPerkins

To make sure air is as fresh as I want it to be, I got this.


Broan HRV80S Broan HRV80S 77 CFM Heat Recovery Ventilator with Side Ports

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1



Provides for HVAC energy recovery.

Pricey but fit for the purpose. We used these in the Northeast when we built superinsulated houses.

Nice design feature for tight builds. Would you consider this part of a 'base build' or nice to have? I rely on the various gaps and leaks in my bus for fresh air, if not actually opening a few vent windows.

[LargeMargeInBaja]

2003, we acquired three propane Wave 3 catalytic heaters for our build.
According to the untested theory, these would supplement our extreme insulation (insulated far in excess of any reasonable definition of rationality...).
.
Why three heaters?
We were unanimously certain we would freeze an untimely death if the outside got below 69°f (metrifical equivalent 12.7 hectares-per-milihour).
.
Real World, winters:
Nearly two decades full-time live-aboard, if the outside temperature dips below 40°f, we occasionally use *one* Wave 3... on the LOW setting of 1,700Btu (metrifical equivalent -- 'combat simmer').
Puttering along on LOW, we adjust our interior temperature with open windows, a half-inch here, an inch there.
A benefit:
* as warm air escapes, it carries humidity.
The floating '40°' about-point is determined by the body-heat fuming from our standard crew -- three RedHeelers plus two adults.
Any warmer than 40°f outside, and our interior is gloriously self-warming.
.
Real World, summers:
We park under trees.
We gain elevation.
We trudge north.
We travel to the coast.
(According to unsubstantiated rumors, moving around are just some of the advantages of living in a vehicle.)
.
We try really hard to keep it simple.
.
.
Our interior is 7w x 12 l x 7h, about 700cf (no metrifical equivalent in the known universe).
Our insulation:
* adhesive-back acoustic against the outer wall
* a gap, then one-inch pink-board
* another air-gap, then two-inch foil-side poly.
.
Over-head vents, fans, air-conditioning, sky-lights?
We decided to wait-n-see on punching holes in a perfectly good roof.
We may wait-n-see another couple decades...

[captnredbeerd]

We have an 8 window international. I put a 15k BTU rooftop ac/heat unit in the rear roof escape hatch. We have a max air vent fan in the front roof escape hatch. We can drive almost anywhere with windows down and max air vent going in the summer and be ok, then plug in at the campsite to get the AC running. In the winter we use the native bus heater or just bundle up—south eastern winters for reference. We eventually rigged up an inverter off of the main bus battery to run the rooftop ac when driving—works decently, never gets cold tho until you’re on shore power. I think I would not like to be without an ac unit of somekind unless you had serious airflow designs—buses get hot. We don’t live in the bus. Just for weekend camping etc.

[TaliaDPerkins]

Originally Posted by captnredbeerd

We have an 8 window international. I put a 15k BTU rooftop ac/heat unit in the rear roof escape hatch. We have a max air vent fan in the front roof escape hatch. We can drive almost anywhere with windows down and max air vent going in the summer and be ok, then plug in at the campsite to get the AC running. In the winter we use the native bus heater or just bundle up—south eastern winters for reference. We eventually rigged up an inverter off of the main bus battery to run the rooftop ac when driving—works decently, never gets cold tho until you’re on shore power. I think I would not like to be without an ac unit of somekind unless you had serious airflow designs—buses get hot. We don’t live in the bus. Just for weekend camping etc.

What insulation do you have, please? Walls, ceiling floor, separation if any from all the glass around the driver's station/front?

[bigskypc50]

I have found the most success with zoned heating and cooling. I have a 40ft bus with three separate zones. Front includes the cab, saloon and kitchen. That is heated via a 42k btu rv furnace and wave 6 heater in off grid mode. On grid is electric heater with the rv furnace as back up. Cooling is done via a 15k portable AC That accounts for half the bus. Zone two is the middle bunk and bathroom. Wave 3 for off grid small mini oil filled for on grid. Zone 3 is the rear master off grid is wave 3 and on grid is a full sized oil filled, and window 5k btu ac.

With that I was able to keep plenty cool 98 degrees in Moab and plenty warm with 10 degrees in MT. Stock celling and windows 1.5” foam in the lower walls and floors. Windows have blackout curtains

[TaliaDPerkins]

Originally Posted by bigskypc50

I have found the most success with zoned heating and cooling. I have a 40ft bus with three separate zones. Front includes the cab, saloon and kitchen. That is heated via a 42k btu rv furnace and wave 6 heater in off grid mode. On grid is electric heater with the rv furnace as back up. Cooling is done via a 15k portable AC That accounts for half the bus. Zone two is the middle bunk and bathroom. Wave 3 for off grid small mini oil filled for on grid. Zone 3 is the rear master off grid is wave 3 and on grid is a full sized oil filled, and window 5k btu ac.

With that I was able to keep plenty cool 98 degrees in Moab and plenty warm with 10 degrees in MT. Stock celling and windows 1.5” foam in the lower walls and floors. Windows have blackout curtains

While I thank you for that answer, no fooling it will take a lot of work and guesswork to develop a spreadsheet of loss rates per unit area to figure out how that compares to my intended situation of all factory windows deleted, triple glazing the windows I put in, and a goal of zero air infiltration with deliberate temperature energy recovery air exchange and 3" spray foam over all. On the other hand ... when I have that, I'll post it.


My goal is to have a 12k mini-split good for 9.6k heating at 0degF heat an cool the 34' of conditioned length for 90% of the year, and run a diesel air heater when traveling and wood stove when not. It should be okay for air conditioning in summer considering the shading ability it will have from solar and awnings.


How tight for air infiltration would you say yours is? Sounds like not so much.

[captnredbeerd]

Originally Posted by TomDPerkins

What insulation do you have, please? Walls, ceiling floor, separation if any from all the glass around the driver's station/front?

We took down the ceiling during build and replaced fiberglass with foam board, then replaced the metal ceiling. Walls the same. Floors have two layers of foam board, then 3/4 plywood then finish floor. Original windows left in place…extra sealed/caulked. No separation from the front, and the original accordion style door which is less than a tight seal if you know what I mean. We’ve got energy losses in the windows and door for sure, but then again, I’m not living in it.

[Mako]

I plan on having 2 mini splits (1 in the rear bedroom and 1 in the front). I also plan on having 2 maxx air fans (1 in the hallway where the bathroom will be and 1 in the front) I am doing this for a couple reasons. If I am on shore power, I can run whatever I want. If i'm using solar, I can alternate between mini splits depending on the day (sleeping/day use) I will be able to shut off rooms if need be to help with climate control. The maxx air fans will be used to get out the humidity from the bathroom and to circulate air when weather doesn't demand the a/c use. My opinion is if you already have it , use it. I always use this line: better to have it and not need it, than need it and not have it...just my 2 cents

[TaliaDPerkins]

Wondering what size, insulation choices, and windows you have.

[Mako]

I have Rv windows installed I will post a pic. I am putting 1" xps and 1/2' polyiso on the floor for a R8.2. I will be using spray foam for the rest of the bus

[Veloc]

Originally Posted by HamSkoolie

The entire roof of our 40' RE will have 4 rails front to rear. Those rails will support a near 100% (vents and such excepted) cover over the roof with an airspace below. This will insulate the roof from solar heating and leave the outside roof temp at ambient in the shade temps. It will also serve to keep snow from sitting on the roof. Most of the space will be covered with solar panels attached to the rails. The remaining area will be covered with wood sufficient to support our weight during maintenance. It WILL NOT be a deck.

Gonna steal that idea, thanks! A second, vented roof over the first sounds like a great idea, particularly for keeping the snow off.

Originally Posted by HamSkoolie

Internally we will have the walls and ceiling professionally spray foamed with closed cell foam. 1.5" on the ceiling and 2-3" in the walls. The floor will have 1" of Owens Corning "Fomular overlaid with 1/2" plywood and then a final floor material.

So as to contribute instead of just take, going to suggest that you have more insulation sprayed on the roof, as heat moves up and not sideways. Regular house insulation minimums, even for extreme climate, are R13 for the side walls, R40 for the roof. I don't recall what the recommendation is for the floor, but I think it's around 20 since it's harder for heat to move through the solid earth than the open air.

[HamSkoolie]

Originally Posted by Veloc

Gonna steal that idea, thanks! A second, vented roof over the first sounds like a great idea, particularly for keeping the snow off.

So as to contribute instead of just take, going to suggest that you have more insulation sprayed on the roof, as heat moves up and not sideways. Regular house insulation minimums, even for extreme climate, are R13 for the side walls, R40 for the roof. I don't recall what the recommendation is for the floor, but I think it's around 20 since it's harder for heat to move through the solid earth than the open air.

"Steal away" that's why we share our ideas on this forum.
As for the 1.5" insulation in the ceiling, that's due to physical restraints. I'm 6'1" and to be able to stand comfortably we had to sacrifice 1/2" on the Owens Corning foam and 1/4" on the plywood (originally wanted 1.5" and .75"). In addition, we're spray foaming the ceiling to the height of the roof bows and then re installing the original metal ceiling (we like that idea but the thermal transfer may be an issue. Our thoughts are that we don't plan to spend much time in cold areas and if it becomes an issue we can overlay it with something to increase insulation.

[cadillackid]

Another advantage to me of spray Doran is it seals up small cracks where drafts can come from where you don’t get that airtight seal with fiber or insulation board that isn’t made to fit perfect

[HamSkoolie]

Originally Posted by cadillackid

Another advantage to me of spray Doran is it seals up small cracks where drafts can come from where you don’t get that airtight seal with fiber or insulation board that isn’t made to fit perfect

EXACTLY why we're going with spray foam. Seals out drafts, won't hold moisture, and leaves no voids.

[Veloc]

Understood. When I eventually start one of these, doing the roof raise partially for that reason. 6ft 4 here.

[HamSkoolie]

Originally Posted by Veloc

Understood. When I eventually start one of these, doing the roof raise partially for that reason. 6ft 4 here.

Yep, at 6'1" I think I can manage, 6'4" would have required a roof raise. Lots more work and expense though if you have a good location (as opposed to a city driveway) it can be done fairly easily, though still a lot of time and money.