Refer Insulation

[Hank Kivett]

My boat is equip with a cold plate...I want to add more insulation around the outside of the box. The problem is between the hull and the box itself..I am toying with the idea of spray foam as well as insulation board.

[Terra Nova]

Originally Posted by Hank Kivett

...I want to add more insulation around the outside of the box...

*Why?*

[Hank Kivett]

Why ?....I have installed solar and at present my refer is drawing the most amps...but installing insulation and some adjustments to the thermostate i can cut the cycles down there by cutting or reducing some amp draw.

[model 10]

Normally one talks about adding insulation to the inside not the outside. I need to add insulation to the inside of our refer.

[crazyoldboatguy]

Hard to add insulation unless you remove the unit, unless you can really gain access. Expanding foam will absorb much moisture and could likely cause problems. The issue is that unless you have 4" insulation around a fridge and 6" around the freezer, ambient moisture/humidity will condense on/inside the expanded foam insulation until it is saturated, reducing the insulative qualities and encouraging more condensation which will seep into surrounding structures, etc. Paradise is so much fun.

[Terra Nova]

OK, so you're saying your reefer/freezer was inadequately/inefficiently built, and you want to improve its efficiency.

Descriptions, photos or sketches showing what you have would help.

Is there a 100% vapor barrier? Radiation barrier? What insulation and how thick? What size box (interior dimensions)?

Edit to add: Front or top opening? What gaskets? And what machinery?

[SV THIRD DAY]

Everything you need to do a nice clean job that will make a difference in your daily Amp usage can be bought in a run to Home Depot. Oh I know, I know the “experts” will wax on and on about pour foam, ripping out your current box, adding $2000 in vacuum panels, but as a bang for your buck project, you just can’t go wrong with adding some Polyisocyanurate insulation to the inside of your box. Cover the insulation with fiberglass “bathroom board” , using 3M 77 Contact adhesive, while sealing the seams with 4200 or 5200 and you have a vapor/water proof insulation panel that will save you Amps.

Easy weekend project. Doesn't matter your box size, shoe size, refrigeration system or current insulation thinckess. Maybe you can only do one wall...so it will still help. Maybe you can only do three walls....even batter. Every wall you can add insulation to will make a difference, so don't let the "perfect" be an enemy of making it "better", especially when you can do it for so little money as a DIY Project. Every inch you add will bring along an R value of 6.5, so stack away baby and save those amps. Most boxes are way to big anyway and have lots of wasted space/volume in them, so why not fill that wasted void with insulation and save amps?

I just helped with this exact project last week in San Diego and have done several myself and if you take your time and be clean, you can get a great clean professional look. The hardest part is making your templates that will fit through your box opening, but it's just a puzzle game piece by piece.

Here are the 5 materials you will need, less some blue tape, large razor knife and beer:

The insulation (available in differing thicknesses)
Search Results forÂ*polyisocyanurateÂ*at The Home Depot

The New refrigerator interrior barrier
http://www.homedepot.com/s/bathroom%...20board?NCNI-5

The Foil tape for sealing the cut edges of the PolyIso Foam
http://www.homedepot.com/p/Reflectix...T210/100318556

The spray adhesive for sticking sticking the foam panels together and attaching the top finish board
3M Super 77 16.75 fl. oz. Multipurpose Spray Adhesive-77-CC at The Home Depot

Our old friend 5200 (I like 4200 fast cure personally, but your choice)
3M 3 oz. Marine Adhesive Sealant-PN5203 at The Home Depot

[model 10]

That was a great post. I am trying to figure out what I can do to our box from what they sell in down town Fronteras, Guatemala. No Home Depot's but there is foam, resin, who knows what else, maybe even some 5200.

[SV THIRD DAY]

The blue and pink boad stuff they have in Mexico isn't as good as PolyIso, but the truth of the matter is if you have **** insulation in the box now even if you use something that's not the best choice...well do it on a temp basis until you can get some better stuff...because it will make a difference.

In our San Diego shop we have a 7FC box that we use for testing and we can add 1" panels of PolyIso to the exterrior of the box ranging from 1" to 8" thick. It's amazing to see the amp hour differences for the different insulation thicknesses. I guess in a way it confrims the laws of physics, but as a data nerd geek, it's still amazing to see what an extra 1" or 2" of insulation can save you in terms of Amp Hours per day.

[autumnbreeze27]

We had a refer company come out and give us a quote for some work on our setup. I used that white foam board you linked to, he said that was no good, as it will absorb water, and that I should use the pink stuff they sell at Home Depot.
Owens Corning FOAMULAR 150 Scored Squared Edge R10 Insulation Board 2 in. x 4 ft. x 8 ft.-45W at The Home Depot
Foamular XPS resists moisture and retains R-value even after exposure to standing water & wet soil.

[SV THIRD DAY]

Originally Posted by autumnbreeze27

We had a refer company come out and give us a quote for some work on our setup. I used that white foam board you linked to, he said that was no good, as it will absorb water, and that I should use the pink stuff they sell at Home Depot.
Owens Corning FOAMULAR 150 Scored Squared Edge R10 Insulation Board 2 in. x 4 ft. x 8 ft.-45W at The Home Depot
Foamular XPS resists moisture and retains R-value even after exposure to standing water & wet soil.

PolyIso is yellow, not white, so not sure if you used the same thing?
But your expert traded an R value of 12.9 for 2" of Polyiso for an R value of 10 (29% worse per inch) for a water absorption worry issue that if PolyIsocyanurate is installed properly isn't something to worry about. (At least not in the life span of you owning the boat anyway.) Heck and if after 10yrs you have to reinsulate for a few hundred bucks and a weekend, I’ll trade that any day for that better 29% in insulation value and all the Amp Hours it will save for the same thickness. This is where the “No good” comment from the experts has to be put in context. The foil covering and using the foil tape on the cut edges is important because you can get this foam without the foil vapor/moisture barrier.

If the moisture issue freaks you out, add a box of heavy duty trash bags to the project list and enclose/foil tape up each piece of polyIso as you puzzle piece them into the box (spraying the 77 Spray in the Bag to attach the plastic bag to the insulation). I personally wouldn't mess with it...but....that's a way to deal with the moisture issue without giving up the 29%....a third less insulation in the same space really matters!

[Terra Nova]

SV--it sounds like you are recommending solutions which you have not tried or proven.

I've never used the insulation you are recommending, so can't speak to it directly. But building a reefer/freezer with insulation that is known to absorb moisture and fail early seems very unwise.

[SV THIRD DAY]

Technautics has been building refrigeration systems and reinsulating boxes for boats since 1968. R-value trumps the relative difference in moisture absorption between the two insulation boards in our view and experience. You may not agree, which is fine, but after years of doing this we are not jonny-come-lately to the reefer insulation game giving shabby information for those looking to reinsulate.

This is where the experts get hung up in our view, but they haven't actually TESTED the water absorption of PolyIso when installed correctly, which is their weak point, because we have. The problem people get into is that they don't have the time or testing facilty to try out the different approaches so they are left with the "this is better than that" comments and advice without a real understanding of the Why and Criteria. If you are building a new boat from the stringgers up, and have 6" of room all around your box then sure, use the closed cell foam that has an R-value of 29% less than the Polyiso. But if you are like the vast majority of cruisers that have an existing box and do not have the space, energy, time, or money to rip up the galley counter but want to improve the **** insulation in your old Box then "R-value for the Inch" wins the day every time = Foil lined PolyIso.

[Terra Nova]

Originally Posted by Terra Nova

SV--it sounds like you are recommending solutions which you have not tried or proven...

Originally Posted by SV THIRD DAY

Technautics has been building refrigeration systems and reinsulating boxes for boats since 1968...

Does avoiding the question mean you have not tried the taped-together-garbage-bag-vapor-barrier you recommended?

[SV THIRD DAY]

Originally Posted by Terra Nova

Does avoiding the question mean you have not tried the taped-together-garbage-bag-vapor-barrier you recommended?

Avoiding? No, not really. Just filtering things out. Which is actually more fun than giving you the answer at this point quite honestly. You do this for a living...so I'll step aside and let you answer your own question, defer to the expert on this one so to speak. Besides, I gotta get back to work, I'm helping with a freezer box reinsulation today here in Morro Bay and I told them I would be over by 9AM to get going...