Radiant Heating Systems

Many energy efficient home designs include radiant floor heat. More efficient than forced-air heating or baseboard heat, radiant heat delivers several benefits to homeowners: less allergens (circulated through the home via the heat systems ductwork) meaning better air quality, reduced electricity usage and fossil fuel usage, and evenly distributed heat at floor levels with little energy loss which means greater comfort and less drafts.

Two types of radiant heat are available: 1) in-floor (most popular); and 2) wall or ceiling radiant panels.

1. In-floor radiant heat:
In-floor radiant heat is by far the most common kind of radiant systems used. There are three types of radiant floor systems: air, electric, and hot water.

Air-heated radiant floors:
Air is not a good conductor; therefore, radiant air heating systems are typically not cost effective in homes and are seldom installed. They can be combined with solar air heating systems; however they would need to be combined with a secondary heating system for non-daylight hours.

Electric radiant floors:
In this type of system, electric wires are built into the floor system or electrically conductive plastic mats are mounted to the subfloor and covered with a floor system such as tile. Electric radiant systems are only cost effective if they have a significant thermal mass such as a concrete floor. This allows you to heat the concrete floor during off-peak electric hours (overnight) and heat the home comfortably for up to 8-10 hours during high-peak electric hours (daytime). Electric radiant floor systems are practical for small additions where an additional heating system needs to be added.

Hydronic (hot water) radiant floors:
Hydronic radiant floor systems are the most popular and cost effective radiant heating system available. Water is pumped from a boiler, hot water heater, or solar collectors through tubing laid under the floor(for wood) or in a concrete or lightweight concrete slab. The tubing can be installed in zones with thermostats controlling the flow of hot water through each zone loop.


2. Radiant panels:
Radiant heat panels are usually made of aluminum and are mounted in either walls or the ceiling of a home. Heat is produced by either electric cables or plastic tubing with circulating hot water. Radiant panels can be individually controlled for each room and have a quick response time, making this heating system an option for rooms that are used infrequently. Wall panels are preferred because of the distribution of heat over the whole body as opposed to ceiling panels, which heat the head and shoulders.

If you’re building a green home, consider installing radiant heat. It creates a warm, comfortable living environment, is easy to install, and gives you a substantial return on investment!

Types of Radiant Heat Floor Installations

Radiant floor heating systems are one of the most energy efficient methods of radiant heat available. Each of the three types of radiant floor heat (electric, air, and water) can be installed using either a “wet” or “dry” installation method.

“Wet” installation methods include embedding the cables or tubing with a solid floor, such as a concrete foundation slab or a thin layer of concrete or gypsum installed over the top of a traditional wood subfloor. Additional floor support might be necessary because of the increased dead load of the materials.


Concrete slab floors have a high heat storage capacity. They do, however, have a slow response time, so it is recommended to maintain a constant temperature for maximum comfort.

“Dry” installation methods include having cables or tubing installed in the air space beneath the floor. This method is faster and less expensive than wet installation methods, but because the radiant heat now involves air space which is a poor heat conductor, the system needs to typically operate at higher temperatures or for longer intervals.

Tubing or cables can be installed between two layers of subfloor with aluminum diffusers to spread the heat across the floor evenly. They may also be suspended underneath the subfloor between the joists using reflective insulation under the tubes to direct the heat upward.

Types of Radiant Floor Coverings

What type of floor covering should you have with a radiant floor heating system? Any floor covering that separates the heating system from the room will decrease the efficiency of the system and affects fuel consumption. Some floor coverings, which act as heat conductors, are better than others.

Ceramic tile, quarry tile and stone are by far some the most common and most energy efficient floor covering because it transfers and stores heat effectively, however almost any type of floor covering can be used.

Carpeting should be minimal in the home. Where required, carpet should be thin and with a dense pad. Carpeted rooms should be zoned separately to ensure even heating throughout the home.

Most radiant floor manufacturers recommend laminated wood floors instead of solid wood, which reduces the possibility of the wood shrinking and cracking as the wood dries, however there are solid wood flooring manufacturers that do support installation of their products over radiant floor systems, observe the plank width limitations if they have them. It is important to follow recommended installation guidelines on any type of floor covering, but the stable even heat o a radiant system is typically considered a good environment for most floor coverings and an extremely comfortable type of heat for your home.

Geothermal Heating Systems

Thinking of incorporating a geothermal energy system into your green home?

Geothermal Heat Pumps, the most common use of geothermal energy systems in green homes, use stable ground or water temperatures near the earth’s surface to provide heating, air conditioning, and in most cases, hot water. Because they use the earth's constant temperatures, they are among the most efficient and comfortable (not to mention sustainable) heating and cooling technologies currently available – and are becoming a popular alternative to oil, coal, and gas. With the ability to deliver comfortable heat even on the coldest days, cost effective equipment, and requiring only a small amount of electricity to operate, geothermal systems are a good consideration for a green home.

Three kinds of systems – Open Loop, Closed Loop, and Standing Column Well Systems – circulate water in pipes below the earth, where water is heated, then delivered into the home for use.

Open Loop Systems are the easiest to install, but because of local codes and the amount of ground water available, are not the most popular kind of geothermal system. In this system, ground water from an aquifer is piped directly to a heat pump inside the home. After it leaves the building, the water is pumped back to the same aquifer by a second well, called a discharge well, located a good distance from the first.

There are three types of Closed Loop Systems available depending on your site characteristics: horizontal ground, vertical ground, and pond systems.

Horizontal ground closed loop systems: If your site permits and trenches are easy to dig, this may be the best system for you. Backhoes or trenchers are used to dig trenches three to six feet below the ground surface and a series of connected plastic pipes are laid in long loops or in a slinky pattern, depending on the amount of area available. A typical system will be 400 to 600 feet long per ton of heating and/or cooling capacity. This system is easy to install while the home is under construction, but can also be installed as a retrofit to an existing home with minimal site disturbance.

Vertical ground closed loop systems are favorable for sites where yard space is limited or rocky, or for retrofitting projects with the least amount of site disturbance. Vertical holes are bored into the ground between 150 and 450 feet deep. Each hole contains a single loop of pipe with a U at the bottom and a horizontal pipe under the ground near the home which carry fluid to and from the geoexchange system. While these types of systems can be more expensive to install, they require less piping than the horizontal loops.

Pond closed loop systems are very economical if your site is near a lake or pond. Polyethylene piping is run underground to the water source, and then long sections of pipe are submerged under the water. While pond closed loop systems do not have any adverse affects on the water source, experts do recommend using this system only if water levels never drop below six to eight feet at its lowest level for sufficient heat-transfer capability.

Standing Column Well Systems are common in the northeast United States. Standing wells are typically six inches in diameter and as deep as 1500 feet. Temperate water is drawn from the bottom of the well, circulated through the heat exchanger, and returned to the top of the water column. Most of the year, they re-circulate water between the well and the water pump, but during peak temperature months, they can bleed some of the water from the system. This causes the groundwater to make up the flow, cooling the column and the surrounding ground in summer and conversely heats the column and surrounding ground in winter, restoring the well water temperature.

Be sure to discuss your plans to implement a geothermal energy system with your local environmental board, check with local authorities regarding permits, and always use experienced contractors.

Small Home Design

One of our clients is building a lakefront cottage on their property in southern New Hampshire for their visiting children and grandchildren to use during the summer months. Some of their requirements included:

• Large porch for entertaining and to capture lake views
• Plenty of bedrooms for extended family
• A first-floor bedroom to address any future accessibility issues
• Plenty of storage for seasonal items
• Large enough common areas (including kitchen, dining, and living areas) for guests to feel comfortable in the cottage when not gathering at the main house
  

The preliminary design addresses these goals nicely. The small home design is based on a traditional cape form with 4 foot knee walls on the second floor with some classic cottage detailing, such as the shingles in the gable dormers, larger rake and eave overhangs. A large 8’ porch provides access to the entry, and wraps around both the side and front of the home to maximize views of the lake and bring the outdoors into the home. The dining room features French doors which open to the porch, and the living room has large windows which also help take full advantage of the lake scenery. A fireplace will help take the chill off of autumn nights.
The open dining / living areas include built-ins for plateware, and the kitchen includes a small breakfast counter and stools. A large walk-in pantry provides additional storage space for the kitchen, and the mechanical room is housed conveniently behind the pantry pass-through door. The L in the stairs provides the perfect spot for an entry closet, while a small bench allows swimmers to towel off and remove sandals before entering the cottage.

A first-floor bedroom includes dual closets and a full bath with whirlpool tub / shower. A large window in the Master Bedroom also looks out over the porch and the lake.

The second floor has three bedrooms for extended family, each having large closets. Dormers allow for additional windows to meet egress and ventilation requirements in the bedrooms. The chimney on the second floor is hidden in a large storage area that can be used for seasonal items.

The efficient design will lend itself to using SIP panels and should provide a fantastic opportunity to heat the home with radiant floor heat if the client chooses to head in that direction.

Architect Fees

Architects use various methods to establish their fees, depending on the type of services they provide, the location of the firm, and their personal preference. In some instances, more than one method may be used to calculate their fees, based on the type of the services provided. Some methods to calculate architect fees include:

• A percentage of construction cost
• An hourly rate, also called “Time and Materials”
• A lump sum
• A lump sum plus expenses
• Unit pricing based on the area of the home
• By the Sheet (the number of drawings generated)

Other factors architects consider are the size and complexity of the project, the difficulty of the site, the timeline, and what services are provided. Architects provide services far beyond a designer or draftsman. Architects are trained to correctly interpret their clients’ dreams, visions and objectives, explore all possibilities, study and respond to the site and its environment, and translate these into a home design that exceeds expectations.

Perhaps you have already designed your home and require little changes and/or aesthetic or structural expertise: in this case, a draftsman’s or designer’s services will most likely fit your needs.

However, if you would like to combine your wants, needs, and aspirations with your goals of energy efficiency and sustainability to successfully match your project objectives, research and interview green architects in your area. Hiring an architect is well worth your investment to ensure the end result is exactly what you wanted.

Residential Solar Energy is HOT!

Solar is the hottest thing in green homes today – and with good reason.

According to The Clear Mountain Solar Store, our local solar experts, “all the potential energy of the earth’s known oil, coal and natural gas reserves is equaled by just three weeks of solar energy. It is estimated that the solar energy that reaches the earth on a typical day could supply all the power the earth needs for a year.”

New government incentives and the explosive growth of the solar industry is great news for people building a new home or preparing a green renovation of their existing home.

Photovoltaic systems can be grid-tied or off-grid, are completely safe, reliable, and require minimal maintenance. Better yet, they produce no carbon dioxide or air pollution.

Heating water for our households accounts for about 25% of our total energy costs. A solar hot water system in New Hampshire and Vermont can produce 70% of your hot water needs and can save an average of 60% - 70% in energy costs, paying for itself in 3-5 years.

You can see even more savings by using a solar space heating system in conjunction with a furnace or biomass stove. Clear Mountain Solar explains, “active space heating systems are most affordable when sized to handle about half of a household’s heating needs. Systems designed to offer more are not cost-effective because most of the excess capacity is only used on the coldest winter days, remaining unused the rest of the year.” A solar space heating system can heat one room, a wing, or the whole home. With a return on investment is between 6-8 years, this type of system pays off quickly while you see the benefits immediately!

One of our one story home plans (pictured above) includes both a solar photovoltaic and a solar hot water system. Now is definitely the time to go green with solar energy!

Resources:
Renewable Energy Resource Center, Burlington, VT

Clear Mountain Solar Store, Claremont, NH

Bonin Architects Hires Intern Architect

I'm very happy to announce a new hire for Bonin Architects: Christopher Timberlake has joined our firm as an Intern Architect.

Chris obtained his Bachelor of Science degree in Architectural Studies and his Masters degree in Architecture from Norwich University, Northfield, Vermont. Timberlake was an architectural designer for a national manufacturer of timber frame homes for five years, and for the past year was head of their design department. Chris is knowledgeable in sustainable design, green building materials, and energy efficient homes.

Chris's professional experience, together with his enthusiasm for architecture, will be a great asset to our company. He's already hit the ground running, working on a few of our current green home designs. Stay tuned!

AIA is Walking the Walk in Green

The American Institute of Architects (AIA) is changing the way we think about buildings, specifically with regard to energy usage. Buildings currently account for nearly half of all greenhouse gas emissions, a fact we simply cannot ignore. AIA architects are leading the way by integrating sustainable design practices in all of their projects, thereby being able to reduce energy consumption to less than half.

This is a strong stand, but a necessary step toward achieving a 50% reduction from the current consumption level of fossil fuels used to build and operate new and renovated buildings by the year 2010. To meet this goal, the AIA started the "Walk the Walk" movement by saying, "We strongly believe that the time for talk has passed, and now it is the time to walk the walk.

AIA architects are uniquely poised to provide the leadership and guidance needed to provide solutions to reduce our national and global carbon footprint. By using sustainable design practices and techniques, such as proper siting, building form, glass properties and location, material selection and incorporating natural heating, cooling, and ventilation and day-lighting strategies, architects design building to operate with far less energy than today’s average home with little or no additional cost.

AIA Architects "walk the walk" on sustainable design. Bonin Architects & Associates is helping you to walk the walk. Are you building a green home in the near future, or thinking about building an addition to your existing home? Call us or visit us at one of our upcoming events, including home shows, green events and seminars, and a Home Tour (May 16th )of an energy efficient home built with SIP Panels by Murus. Learn more about how you can lower your home’s energy consumption and play an active role in, well … saving the earth.