High Mark Mechanical specializes in Installation, Service, Repair, and design of all radiant heat systems and equipment. Boiler replacement, gas conversions, leak repair, control work, piping leaks, and annual safety checks are what we do.
Radiant or Hydronic Heating is defined as utilizing hot water to heat the space in your house. This means that water is circulated through pipes from a heat source like a boiler or water heater to either free standing radiators, baseboard radiators or under-floor pipes. The water is used to transfer heat from the heater to the rest of the house as opposed to warming air directly. This type of system is very quiet, very efficient, doesn't move dust around and has a very long life span. It is space saving and suitable for retrofit of older buildings due to the smaller in-wall, in-floor space needed for pipes (instead of ductwork).
Endless Hot Water Supply
Navien Condensing 98% Tankless Water Heaters provide an unlimited amount of hot water at a steady temperature, whenever you need it, for as long as you need it.
Ultra Condensing Efficiency
Because this product boasts the industry's
highest efficiency, rating (98%) means
customers can cash in on low annual operating
costs as well as receive the best payback,
compared with conventional tankless or tank-type water heaters. Navien's Condensing 98% Tankless also enjoys the highest gallons-per-minute (GPM) when comparing input BTUs.
Built-in Circulation Pump with Mini Buffer Tank "A" Models Only
- Delivers hot water to fixtures quickly resulting in water conservation
- No minimum flow rate: get hot water even at very low flow rates of 0.1 or 0.2 GPM
- Eliminates any hot/cold/hot stacking, the so-called "Cold Water Sandwich"
- Saves additional money and time by eliminating pump purchase and on-site installation costs
- Prevents heat exchanger from freezing.

These water heaters utilize a draft diverter and are atmospherically vented with capacities ranging from 29 to 60 gallons and inputs ranging from 30,000-50,000 BTU's. These models are perfect for many standard water heating applications.
General Plumbing
Drain Cleaning
Gas Fireplaces
Furnaces & Heat Pumps
Boilers & Hot Water Systems
Excavation & Snow Removal





