Laars Mini-Therm Boiler Overview

The Laars Mini-Therm boiler is a gas-fired residential hydronic boiler series. This series is available in two models, the JVS spark ignition and JVH hot surface ignition with induced draft. Both models can be equipped with natural or propane gas.

The Mini-Therm JVS line offers 85 percent AFUE in six different models with either single or two-stage heating. Energy-saving components of this model include a low/high function that allows homeowners to set the amount of heat disbursed, a built-in draft diverter to retain more air, and automatic vent damper.

Similar to the JVS, the JVH product line is manufactured in six models, but is only available with single-stage heating. This model is equipped with a hot surface ignition system, induced draft system and offers up to 83 percent AFUE.

Both the JVS and JVH product lines feature the Laars copper tube heat exchanger with small cast-iron wet-walls to increase functionality, low-mass heat exchanger and quick heating response.

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Consumer Reviews of Laars Mini-Therm


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #2 of 8 Laars Boiler
  • 45.45% of customers recommended

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Laars Mini-Therm Boiler Reviews

Showing 6-10 of 11 reviews

"Should have read the reviews first"

1.0 rating
Very Unsatisfied

I called a mechanical company who has served us well in the past. When they sourced the boiler, they said all their wholesalers recommended the Laars boiler. Well, after a 3 day install, which should have been a quick swap, we have been 2 weeks without heat. The installer and now the specialist technician can't get it to start up. This is a brand new unit, which supposedly left the factory working. We have $8000 in, and now it sounds like we'll need to remove it and go with another brand. I'm bracing for another $3-5000 to get a boiler. We are devastated. Wish I had a furnace! People with forced air should be delighted they don't have to worry about it.

Patrick H.

Edmonton, AB

"Minimal problems in 20 years"

5.0 rating
Very Satisfied

The unit was oversized, which caused cycling and which led to a piece of the flue rusting out. I turned down the gas flow and checked the flue every couple of years, cleaned the boiler fins and vacuumed. I had a failure this winter with the diagnostics board, so $160 later installed one but it did not correct the problem. It turned out to be a blown fuse. Egg on my face. My father-in-law has an NTI and I would not swap my inefficient Laars for that piece of crap, no how. I could replace the board, gas valve, relays and aquastats for the cost of one of his service calls, and they are a routine occurrence.

Frank K

Edmonton, Alberta

"Laars Mini Therm JVS 50"

5.0 rating
Very Satisfied

I have noticed on this forum that the Model Numbers don't come up. Laars has many different models out there. Some I don't install. On the other hand, where I need to raise a boiler off the floor, usually for water reasons, I have used the Mini Therm with great success. It has been around for a long while. Improvements have been made along the way. Both the supply and return are now 1-1/4" instead of the old 1" connections. They also recommend primary/ secondary piping on the boiler. These changes have pretty much eliminated any problems the boiler might have had. The two problems were connected to water circulation. First cold return water traveling through the copper heat exchanger caused condensation which would help clog the passageway through the heat exchanger. The addition of a primary/ secondary pump, eliminated this problem. That same pump system solved the problem with whistling/ and or knocking on the high temperature part of the heating cycle. This same primary/ secondary piping is used on just about every high efficiency boiler on the market now. And if that primary pump fails, you will either get the knocking (water turning to steam) or a boiler lockout on high temp.

Dick S.

Humarock, MA

"Every year a problem since we bought it"

1.0 rating
Very Unsatisfied

This boiler has a problem every year since we got it. Stay away from this brand.


Jersey City NJ

"Hydronic Boilers Laars"

1.0 rating
Very Unsatisfied

Have a laars jvs 160 nk hu 2 installed: after a year of operation the boiler stared to leak, (I was thinking condensation). I was wrong. Second winter roller in, the boiler failed on 30 of Dec, went to see what going on. The boiler had been on fire, all of the controls are blacken, black smoke stain all over the walls. The circuit breaker did not trip and the wiring looked like brunet spaghetti, burnet plastic smell all over the house, the heating core was leaking and water was dripping on the gas burners. There is a 12 inch vent a with a T drip pan, (up to code or LAARS installation standards). The plumber removed the boiler LAARS electric damper was stuck open, the vent was open on the outside of the house (The LAARS REP said: they have see roll outs that were cause by snow covering the vent' Not the case here'). The panel that has LAARS controls on, shows positive signs of electrical ARC FLASH from the control board. (They only warranty the boars for 1 year). The heating core is clearly leaking and now they came back and tell us that they will not stand by their warranty unless we buy another boiler from them, plus the factory has to prove that fire was caused by poor workman ship of the boiler. The company is forcing us to buy their product again, I feel like we are working with cartel! From my experience; LAARS customer services earn a rating 1 out of a scale of 1 to 10. The company controls boards are made from third world country and have a life cycle design of 1 year. As to the heating core all I can say if the board are a extra poor grade then the heating core is to. And they will take you for a ride and rape your wallet. Never buy a LAARS boiler and replace the one you have before there a ARC FLASH in your house



Other Mini-Therm Reviews

Several consumers around the web post negative comments and concerns regarding the Mini-Therm boiler�s performance. Forums such as and have several posts indicating homeowners purchased “lemon” units; these consumers mentions their units have repeatedly broken down over the years.

Frequent errors reported with the Mini-Therm include system lockouts, melted electronic controls and failing rollover switches and other components. Costly repairs and the frequent resurfacing of these troubleshooting issues are common grievances aired by homeowners in other review forums. Contractors attribute some of these problems to poor venting, and others to the unit itself. also rates Laars systems poorly, stating the warranty coverage is not as good as other brands and the components may not be as durable.

LAARS Mini-Therm Model Numbers

The Mini-Therm is available in different models which vary in efficiency and capacity.

Model Number AFUE BTUs per Hour
JVS050ND* 84.4 50000
JVS050PD* 85.4 50000
JVS075ND* 84 75000
JVS075PD* 85.2 75000
JVS100ND* 84 100000
JVS100PD* 85 100000
JVS125ND* 83 125000
JVS125PD* 84.5 125000
JVS160ND* 83 160000
JVS160PD* 84.8 160000
JVS225ND* 83.2 225000
JVS225PD* 85 225000

Mini-Therm Warranty

Laars provides a 1-year limited warranty for all parts. In addition, the integral storage tank is equipped with a 10-year limited warranty and the primary heat exchanger is covered on a pro-rated basis for 20 years after the installation date.

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