The problem with insulating well is that I need a very small(<3KW) eletric boiler. I know this sounds like a desireable "problem" but the issue is that there are not a whole lot of suppliers of electric boilers for heating in the 3KW range. Here are the few I have come across. I am assuming I need an ASME-H certification for code compliance here in the US, so some of these may be non starters for that reason. Does anyone have any experience with any of these? Any input on models I missed or suggestions would be appreciated...
Electro MINI-Boiler EMB-H-5 240VAC, 4.5KW modulating CSA US and ASME H ratings.
This boiler has contactor for circulating pump, but does not provide power for the pump.
Their units this size have no outdoor reset. and a 90F low limit(a little higher than I would like).
4.5KW output is about 218% of my max calculated heat load. They make smaller ones,but they are 120V models and I want to keep my load balanced as I occasionally run on generator power. There are ways to accommodate this though so they might still be an option at increased complexity.

Thermolec B3TMB 3KW 240VAC Modulating but this model does not appear to have a ASME rating(I am clarifying this with a sales rep).
Contactor for circulating pump, but does not provide power for the pump.
Has outdoor reset and 80F low set point.
3KW is 145% of my max calculated heat load.
They make the FFB(H) series that does have an ASME rating, but at 6KW with a single element it is way too large. I have a question in to them IRT a custom unit with one or two 3KW elements. With two elements, only one would ever run, but it would give me some installed redundancy and I like that...

Thermo2000 Mini-ultra 240VAC, 3KW, Modulating, CSA US and ASME H ratings.
Pump control AND pump power supplied by unit.
Multiple inlets and outlets, can be mounted horizontally.
Outdoor reset and outdoor shutdown, 85F low set point(might be lower, awaiting clarification from manufacturer).
Digital controller/panel that allows easy adjustment of features and pump control.
This one looks to be the most versatile, and would probably be the easiest to install. The 6KW model uses two 3KW elements so would add the same built-in redundancy as a custom thermolec(if that is even possible).

Concept manufacturing(lion boiler) LEB-3 240VAC 3KW Modulating/staging. Also appears to only be CSA rated(awaiting clarification from manufacturer on this).
Pump control AND pump power supplied by unit.
No outdoor reset, 60-120F temperature range.


Thanks

Please keep in mind that short cycling is not hard on electric boilers like it is on NG or LPG boilers. Electric boilers are also easy DIY installations. Of your list, we can recommend the Thermo 2000 6KW Mini Ultra Boiler having installed several without any issue. You might also want to look at the smallest Argo and Slant Fin models. Some of these have multiple elements and will use the minimum number of elements required to meet the actual demand. Here’s one example:

http://s3.supplyhouse.com/product_files/SeriesC-Brochure.pdf

We have been a distributor of Thermolec products for many years now.
These are a good choice. We actually manufacture pre assembled boiler panels using these units and have found them to be very trouble free in operation.
http://www.blueridgecompany.com/hydronic/pump-distribution-panels/rht-prefabricated-electric-boiler-panels/392
This link will provide you with an idea of how typical plumbing can be accomplished on an electric boiler (Thermolec or otherwise).
I can personally recommend these as a good choice for multiple applications, The small TMB series while not having a H stamp does have the same pressure vessel and heating elements as well as an out door reset.
The key with electric boilers is maintaing flow through the boiler to avoid overheating. Minimum flow requirements are listed in the Thermolec install manual.
H stamp is a pressure vessel certification, it may or may not be required in you're building jurisdiction. A check with local code enforcement can answer that.
Dan

Thanks for the info/links. I hadn't looked at any of the Argo boilers yet. They came up in my searches, but I don't recall seeing one that small(6KW)

Dan, I like those panels, especially the stainless manifolds...

Dan has the plan. We use Electro and Thermolec, which has a stainless tank and smoother weather responsive controls. In fact I own one of each.

All the electric boilers mentioned are good units. Here is another up and coming one we stumbled upon and may use. www.nextgenboiler.com

Thanks Jonny, I finally got a chance to look at Nextgen. That is basically a whole system in a box, just add manifolds and loops...

Electric boilers need to be of good unit.

What sort of price did you find on prices for the nextgen? That seems like a nice unit

About 1800

Ya, we purchased one recently for about $1500.00 from our wholesaler. I guess it depends if you are trying to purchase at end use cost then $1800.00 seems appropriate. The install went super easy, less than an hour to pipe it. It has some cool features not found on other electric boilers with feedback from the control panel that indicate BTU output, flow rate, pressure and temp readings. It also is capable of outdoor reset, post -purge on the pump. Also the pump exercises in the summer. I know our customer really liked how it worked and that it was all housed in a pleasing looking cabinet. So far thumbs up on this NextGen Boiler.