Hydronic (Hot-water) Heat

Hydronic heating is a method of heating that uses hot water or steam, instead of air.  A hydronic heating system takes advantage of water's superior conductive properties to heat your home more efficiently by heating the objects in it-not the air.  

It depends largely on the delivery of heat directly from a hot surface to the people and objects in the room via the radiation of heat.  It's the same effect you feel when holding a mug of coffee in your hands or the warmth of a hot stovetop element from across the room.

Hydronic Heat vs. Forced Air Systems

Forced Air system is a type of heating system in which heated air is blown by a fan to rooms and since warm air rises and cold air sinks, it's always coldest on the floor.  Our body temperature is warmest at our head with circulation being poorest at our feet, which is why we are most comfortable in a room that is warm at the floor and slightly cooler at head level. 

It's easy to see why a forced air system produces a much lower comfort level than a hot-water heating system and why a forced air furnace has the highest monthly energy costs of any heating system.

heat distribution

Heat distribution with forced air is uneven. Most of the air is concentrated at the ceiling, where it is lost to the outdoors. With hot water heat, it is warmer closer to the floor where heat is needed. So you are more comfortable at a lower thermostat setting, thus saving on your fuel bills.

Ah, the pleasure of heat and hot water!  Lynda is convinced the house heats faster!  We are pleased in every way with your work. Riley and Dennis were a pleasure to have in the house and Riley put the frosting on his copper/brass solder sculpture by leaving the work space in immaculate condition. Please use us for an enthusiastic reference any time. Thank you!

- Lynda and Doug, Seattle

Benefits of Hot-Water Heat


No other heating system can compare with the even, natural warmth of heating with water.


Dust, air contaminants, bacteria, and low humidity levels, all problems associated with forced-air heating, are nonexistent in a home with a properly designed hydronic heating system.


Heating with hot water will save you 5 to 20% over forced-air heat.


You decide the level of control.  From heating the entire house with one thermostat to setting each room's temperature individually, the choice is yours.


The options to heat your home are almost limitless; choose from old-fashioned cast-iron radiators, modern wall panels, baseboard heaters, radiant floor or ceiling heat, heated towel bars and tub/shower heat.

Expert Installation

Whatever system you select, be assured that the trained, experienced craftsmen at Carlson Mechanical will install it expertly and control it in a manner to enhance your comfort, keep your heating costs low, and ensure that your investment will be long-lasting and trouble free.

Thank you so much for your recent fine work coordinating the removal of our old oil-fired boiler and then installing a new Viessmann gas-fired boiler. Thanks for delivering so well on the promises you made during our initial conversations, for being such a pleasure to work with during the project and for ironing out wrinkles as the new system has begun to heat our home.

- Geoffrey, Normandy Park
Customer since 2008

So, how do you deliver radiant heat to the house?

There are several delivery system options.

Cast IronCast-iron radiators

Cast-iron radiators are suitable for both residential and commercial applications.  Cast-iron radiators supply a continuous flow of heat.  The radiant heat combined with convected heat creates a warm comfortable environment.  It shields outside walls and windows to stop cold air from infiltrating-right where it starts.  After the boiler has run full cycle, the hot water in the radiator sections continues to emit gentle heat.  The end result is a cozy room with less than a two-degree temperature variance from floor to ceiling.

BaseboardBaseboard heaters

Baseboards provide space heating in both residential and commercial applications.  The baseboard is inconspicuous, but an effective distributor of heat by disbursing heat, both horizontally and vertically.  A baseboard panel does not blow air or stir up dust and their operation is virtually silent.

PanelPanel Radiators

Panel radiators combine art and science to deliver a modern, attractive heat with incredible comfort at a reasonable price.  Panel radiators offers a clean solution to heating problems as it does not blow air or stir up dust and the operation is virtually silent.  Both Buderus and Runtal offers a variety of panel-style radiators for your home or business.

Floor HeatRadiant Floor & Ceiling Heat

Nothing delivers comfort better than radiant heating.  Radiant heating heats your body and objects, not the air.  With radiant floor heat, the warmth stays down around the floor where it is needed most.  The systems circulate warm water through flexible tubing that can be installed underneath virtually any type of flooring material—wood, tile, even carpet.

Radiant ceiling heat is perfect for remodeling projects, additions and for heating the upper floors of your new home.  Tubing and heat emission plates are attached to the ceiling joists or sheetrock.  The ceilings radiate heat to people and objects much like radiant floors.

Heated TowelHeated Towel Bars

Make getting out of the shower more comfortable with these attractive heated towel bars.  They keep your bathroom dry and free of mildew, germs and musty smells.  Each towel rack acts as a radiator-an adjustable source of heat for the room.  Their low profile fits minimal space requirements (depth 4”), and they coordinate easily with any bathroom décor.