In our last post about Dwell Developments project 1105 dwell, we talked about creating a comfortable, healthy efficient interiors within these homes. Specifically we touched on the Heat Recovery Ventilators they have installed. These HRV’s will keep the homes supplied with plenty of air, manage indoor moisture, and will do so in a very efficient manner.
Another one of the many unique features of these homes is the choice they have made to heat the interior spaces and meet the homes domestic hot water needs. The single piece of technology they have chosen for these purposes is a Navien Condensing 98% Water Heater. This is an all-in-one unit comprised of a boiler that heats the water as needed and utilizes heat exchangers within the unit to deliver the proper temperature water for the radiant heating while simultaneously delivering hot water for use in laundry, dishwashing, showers/baths, and sinks.
The Navien system is 98% efficient meaning that out of every dollar spent to heat the water only 2¢ worth of that energy is lost to the exhaust. The way this is achieved is through heat exchangers. These units are equipped with two heat exchangers; one for turning cold water into hot and the other being a condensing heat exchanger that uses the condensation that is created as a result of the cold water cooling the hot gases inside the unit. Normally these hot gases would escape through the vents in a conventional hot water heater. In this case the heat in the condensation is utilized to help heat the water, dramatically increasing the efficiency of the unit.
Both for the radiant heat system and for domestic hot water it is necessary to bring the water to a specific temperature. This is achieved by sending the hot water through mixing valves that are controlled by a thermostat to deliver just the right temperature water on a constant basis. These mixing valves will introduce just enough cool water to the heated water to maintain the desired temperature. With the capabilities of the Navien unit homeowners can enjoy a virtually endless supply of hot water.
At 1105 dwell the radiant heating systems has been installed in two seperate applications. On the lower levels the pex tubing has been embedded in the concrete floors. Heating this concrete slab creates a significant amount of thermal mass that can be taken advantage of for heating during cooler months. In the warmer months of the year this same thermal mass will contribute to the cooling of the home as it will remain cooler that the air that surrounds it when it is not being heated. On the upper floors the radiant heat is being delivered through the same pex tubing, however in this case the application method is known as staple-up. It is just what it sounds like. The tubing that carries the heated water is attached to the sub-flooring with large staples that stradle each side of the tube. The contact the tubing makes with the floors in combination with the insulation that has been placed between the floors will direct this heat into the flooring surface and spread that heat evenly across the interior spaces.
Radian heat provides a comfort at lower thermostat settings, aides in healthy indoor air quality, is quiet, and greatly reduces drafts in homes. On demand hot water systems are an efficient, space saving means of providing an ample supply of hot water as it is needed, rather than maintaining a volume of heated water even when it is not in use. These are just a few of the ways that these homes will give back to their homeowners just as much as has gone into their design and construction.
If this is the first post you have read about Dwell Developments 1105 dwell project take a few minutes to look back through past posts. These homes are available for presale and we are happy to coordinate site tours for interested homebuyers as well as those of you who may just be interested in seeing how these homes are constructed up close. We will cover the remaining aspects of these homes construction in future posts and encourage your comments and feedback.
Filed under: Seattle Green Building | Tagged: Design + Build, Dwell Development, Green Building, Green Home Tours, Green Homes, Green Homes For Sale Seattle, On Demand Hot Water, Radiant Heating, Seattle Green Building
