Experiences and lessons learned on one house doctor's journey between countries east and west
In the spring of 2009, I made my first journey to Europe with the intention of discovering my roots and exploring why we in the United States use twice as much energy on average as do citizens of European countries. What do the energy technocrats of Europe have to offer? What are they doing to existing residential buildings to make them more energy efficient?
Europe’s housing stock is much older than ours. It is also much smaller on average. One of the first things I noticed in Europe was how compact the people’s lives are. Smaller refrigerators, smaller clothes washers, smaller rooms, smaller vehicles, and smaller coffee cups.
A study done by the BBC showed that the floor area of the average U.S. home is 2,300 square feet; of the average French home, 1,215 square feet; of the average UK home, 818 square feet. Population density in North America: 32 people per square mile, compared to Europe: 134 people per square mile. Motor vehicles in Europe get an average of 43 mpg versus 24 mpg for motor vehicles in the United States. This could help to explain the difference in energy use.
Back in the United Kingdom
Most homes in Europe are built almost completely without wood, while U.S. homes are typically wood framed. Bricks used in European residential construction are larger and have more holes than bricks made in the United States. European construction also uses concrete for the walls and floors, while U.S. construction usually uses concrete only for the foundation walls. The masonry provides more thermal mass than the brick or wood-stud walls of the United States, but most European homes have little or no insulation in the walls.
Armed with these general rules of European construction, I made my first stop in London, to visit friends. Being a house doctor and in the city of Sherlock Holmes, I did my first investigation of building science in my hosts’ flat. Noticing the nice enameled cast-steel hot water radiators, I inquired as to the whereabouts of the boiler.
Opening a small closet door in the living room and pulling back the curtains, they pointed to a small, wall-mounted direct-vent condensing boiler unit. I thought, “Wow, nice boiler, very compact and efficient.” They went on to tell me that they really had no choice; they were legally required to select a very efficient unit.
In the UK, boilers are rated by the percentage of the fuel they consume that is converted to heat. This rating is called SEDBUK, or Seasonal Efficiency of Domestic Boilers. Like the EU energy label ratings described below, SEDBUK ratings range from A to G, with A-rated boilers being more than 90% efficient. Standard efficiency boilers are rated D, and their high-efficiency counterparts are rated A or B.
In 2004, the government predicted that the UK’s native gas reserves would run dry in 12 years—the UK now imports more gas than it produces. This has resulted in higher gas prices; and the problem can only get worse as demand for ever-decreasing gas supplies increases. On April 1, 2005, it became legal to install only A- or B-rated rated boilers. These A- and B-rated boilers use condensing technology to convert more than 88% of their fuel into heat, compared to 78% for conventional boilers.
European Union Energy Policy
The European Union (EU) is a unique economic and political partnership between 27 European countries. It launched a single European currency and is building a single Europe-wide market in which people, goods, services, and capital move among member states as freely as within one country. The European Commission is the EU’s executive body that represents the interests of Europe as a whole. A new team of 27 Commissioners (one from each EU country) is appointed every five years. On June 22, 2011, the European commission released the proposal for a directive on energy efficiency. The directive aims to help member states step up efforts to use energy more efficiently at all stages: from the generation and transformation of energy to its distribution and consumption. The Energy Performance of Buildings (EPBD) introduced in 2005 had a very ambitious goal: reduce European building energy consumption by 10% by 2010 and 20% by 2020. The directive states that “energy saving is without a doubt the quickest, most effective, and most cost-effective manner for reducing greenhouse gas emissions.”
Nonetheless, recent projections by the European Energy Commission suggest that the EU is on course to achieve 10%, rather than the 20% objective. To give fresh momentum to the EU’s energy-saving efforts, on March 8, 2011, the commission put forward a new Energy Efficiency Plan (EEP), setting out measures to achieve further savings in energy consumption. The plan states, “The greatest energy-saving potential lies in buildings. The plan focuses on instruments to trigger the renovation process in public and private buildings and to improve the energy performance of the components and appliances used in them. It promotes the exemplary role of the public sector, proposing to accelerate the refurbishment rate of public buildings through a binding target and to introduce energy efficiency criteria in public spending. It also foresees that utilities will be obligated to enable their customers to cut their energy consumption.”
In regard to buildings, the plan further states, “A large energy-saving potential remains untapped. Techniques exist to cut existing buildings’ consumption by half or three-quarters and to halve the energy consumption of typical appliances. But the renovation rate of buildings is too low, as is the uptake of the most efficient appliances. The barriers to energy-efficient buildings need to be overcome. The Commission invites Member States to establish promotion systems for private-sector buildings.”
The EU energy label rates products from A (the most energy efficient) to G (the least energy efficient). These ratings are used on lightbulbs and household appliances such as refrigerators and washing machines. On June 19, 2010, the EU introduced a new energy label layout, which retains the uniform and simple design of the old label across the different product categories, while adding three new categories for refrigerated appliances, washing machines, dishwashers, and televisions. These new categories are for the need to go “beyond A.” This allows manufacturers to compete further by developing products that are more and more efficient. The information is thus provided to consumers who can then make well-informed choices. Also, the new label is language-neutral, as text is replaced by pictograms that inform consumers about the characteristics and performance of a given product. (See label at right, below.)
Tackling Heat Use in Buildings
Addressing heat consumption in buildings is of prime importance in most of Europe. As I mentioned, the building stock in Europe is old, which presents problems when it comes to energy retrofitting. This is the reason that heating systems are often the first item to be upgraded, and high efficiency equipment seems to be more accepted there.
Also, the use of district heating is being promoted and implemented. District heat is a method whereby one heating plant supplies many end users through the use of an insulated utilidor. It is usually a high-efficiency boiler that can supply both heating and domestic hot water. It works better in densely populated areas and makes the most sense from a long-term investment perspective. It can be set up to use multiple fuels, and a cogeneration plant (also called combined heat and power, or CHP) is often added in addition to the boilers. The combination of cogeneration and district heating is very energy efficient. A simple thermal power station can be 20–35% efficient, whereas a more advanced facility with the ability to recover waste heat can reach total energy efficiency of nearly 80%.
Today more than 40% of windows in the EU are still single glazing, and another 40% are early uncoated double glazing. The commission will work to facilitate the market uptake of more-efficient building components, for example, by mandating energy labeling for windows.
In Europe, like the U.S., there is a need to upgrade the electrical supply grid. The European Commission recognizes this and is developing legislation to move in the direction of Smart Grids. Smart Grids could be described as an upgraded electricity network to which two-way digital communication between supplier and consumer, intelligent metering, and monitoring systems have been added. Smart Grids can also manage direct interaction and communication among consumers, households, companies, other grid users, and energy suppliers. Improved and more targeted management of the grid translates into a grid that is more secure and cheaper to operate. Smart Grids will be the backbone of the future decarbonized power system. Member states are obliged to roll out smart electricity meters for at least 80% of their final consumers by 2020. So far, there is about a 10% implementation of Smart Grids in the EU, with an average of 10% reduction in consumption by consumers. Of course, the upgrades come at a cost; so far 5.5 billion euros have been invested.
A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems (Adamson 1987 and Feist 1988). The house heats and cools itself; hence, it is "passive."
For European passive construction, prerequisite to this capability is an annual heating requirement that is less than 15 kWh/(m2a) (4755 Btu/ft2/yr), not to be attained at the cost of an increase in use of energy for other purposes (e.g., electricity). Furthermore, the combined primary energy consumption of the living area of a European passive house may not exceed 120 kWh/(m2a) (38039 Btu/ft2/yr) for heat, hot water, and household electricity.
With this as a starting point, additional energy requirements may be completely covered using renewable energy sources.
A passive house is cost-effective when the combined capitalized costs (construction, including design and installed equipment, plus operating costs for 30 years) do not exceed those of an average new home.
This means that the combined energy consumption of a passive house is less than the average new European home requires for household electricity and hot water alone. The combined end energy consumed by a passive house is therefore less than a quarter of the energy consumed by the average new construction that complies with applicable national energy regulations.
Following are the basic features that distinguish passive house construction:
Compact form and good insulation
All components of the exterior shell of the house are insulated to achieve a U-factor that does not exceed 0.15 W/(m²K) (0.026 Btu/h/ft2/°F).
Southern orientation and shade considerations
Passive use of solar energy is a significant factor in passive house design.
Energy-efficient window glazing and frames
Windows (glazing and frames, combined) should have U-factors not exceeding 0.80 W/(m2K) (0.14 Btu/h/ft2/°F), with solar heat-gain coefficients around 50%.
Building envelope air-tightness
Air leakage through unsealed joints must be less than 0.6 times the house volume per hour.
Passive preheating of fresh air
Fresh air may be brought into the house through underground ducts that exchange heat with the soil. This preheats fresh air to a temperature above 5°C (41°F), even on cold winter days.
Highly efficient heat recovery from exhaust air using an air-to-air heat exchanger
Most of the perceptible heat in the exhaust air is transferred to the incoming fresh air (heat recovery rate over 80%).
Hot water supply using regenerative energy sources
Solar collectors or heat pumps provide energy for hot water.
Energy-saving household appliances
Low energy refrigerators, stoves, freezers, lamps, washers, dryers, etc. are indispensable in a passive house.
Programs in Individual Countries
So what are the individual member states doing to implement energy efficiency in the building sector, specifically in the residential building sector? Following are some examples.
In Germany. In Germany, regular inspection of boilers has been mandatory for many years. If a boiler does not comply with the requirements, it must be replaced. The inspections are carried out by the local master chimney sweeper on behalf of the competent authorities. Furthermore, it is mandatory that boilers installed before 1978, which do not comply with the status of low temperature boilers, are exchanged for highly efficient boilers. Financing is available with a subsidized loan through the Federal Promotional Bank (KfW Förderbank is a German government-owned development bank, based in Frankfurt). Thus, thousands of boilers are replaced every year, which results in a reduction of the average age of the boiler stock in Germany.
In 2003, Dena—the German equivalent of the U.S. DOE—initiated the pilot project called Efficient Homes. As part of the project, over 330 buildings were upgraded to achieve high energy efficiency. (In some cases highly innovative Passive House components were used. See “Passive House,” p. 46.) These homes now consume 30–60% less energy than a comparable new building.
Dena’s requirement that a refurbished building consumes 30% less than a comparable new building has been adopted by the CO2 Building Rehabilitation Programme of the Federal Promotional Bank (KfW Förderbank). This new program started in April 2009. The loans and grants issued through this program are based on energy standards of five levels. Simply put, the figures indicate in percent how much of the maximum primary energy requirement the house consumes. The best standard (55) receives the highest support. In order to meet the high energy standard of a KfW Efficiency House, extensive investments, such as the renewal of heating systems, thermal insulation and replacement of windows, are usually required.
In France. The French Plan Climat 2004 set a national objective of reducing CO2 emissions by a factor of four by the year 2050. The plan seeks to achieve this objective by increasing energy efficiency, and to do so, it has established two tiers of crédits d’impôt, or tax credits.
For efficient boilers, insulation, and energy meters, the tax credit is 25% of the amount invested. For renewable-energy production, the tax credit is 40% of the amount invested.
In Denmark. In February 2004, the Danish Energy Authority directed window manufacturers and installers to phase out traditional double glazing over a three-year period, and thereafter to manufacture and install only highly efficient windows with low-e double glazing or better. This has changed the market to one in which energy-efficient windows are standard, and windows are rated and labeled from A to G.
In Denmark, there are rules to ensure that both existing and new boilers and heating installations are as energy efficient as possible. Oil boilers are required to be inspected annually. New oil-fired boilers must have a partial-load or full-load energy efficiency of at least 91% and therefore cannot be rated lower than C. New natural-gas boilers must be condensing.
In the UK The UK, which is not a member of the EU, gives landlords tax credits for energy-efficient upgrades as assessed by the UK’s Standard Assessment Performance (SAPs) building energy rating system. The Carbon Emissions Reduction Target (CERT) came into effect in April 2008. CERT obligated electricity and gas suppliers to help reduce residential CO2 emissions. This may be one of the most aggressive programs in Europe so far. Electricity and gas suppliers will be obliged to promote the use of materials and practices that improve energy efficiency—for example, loft and wall insulation. A press release dated September 7, 2011, issued by the UK’s Department of Energy & Climate Change states, “Almost 300,000 insulation measures such as loft and cavity wall insulation have been installed in British homes over the past three months, new figures published today reveal.” This brings the total number of British homes that have adequate loft insulation to 58%, and the total number of homes with cavities that have adequate cavity wall insulation to 58% likewise. But Energy and Climate Change Secretary Chris Huhne also warned that the six major energy suppliers—British Gas, EDF Energy, E.ON, npower, ScottishPower, and Scottish & Southern Energy—are at risk of missing the government’s tough home energy efficiency targets and need to double their insulation rates. It is estimated that companies will have to double their monthly professionally installed insulation rate from the average 100,000 a month seen since last year to some 200,000 if they are to meet the insulation target.
There is also a renewed drive to ensure that more vulnerable households receive support. Suppliers were already required to meet 40% of their total target by delivering measures to a “Priority Group” of vulnerable and low income households, including those in receipt of eligible benefits and pensioners over the age of 70. Under the extension, an additional target has been introduced to require that 15% of the savings be achieved in a subset of low income households (a “Super Priority Group”) considered to be at high risk of fuel poverty. Companies will have to increase the rate for this group from an average 5,000 installations a month to 18,000 a month.
Paris, Oh Là Là!
Next, by train and ferry, I was off to Paris and the Alliance to Save Energy Efficiency Global Forum. EE Global 2009 gathered 600 energy efficiency advocates from over 30 countries. Over 40% of EE Global participants were self-identified as executives, and another 50% were self-identified as managers. (I was severely underdressed, and had to go find some fancy clothes to fit in.)
Over the course of three days, I heard from leaders in the private and public sectors as they shared insights and information on the latest energy efficiency policies and technologies. I was a little disappointed; I was hoping to see more of the advanced energy technologies that I dreamed existed in Europe—leading-edge products I could touch and feel. But instead, I got to hear from the bureaucrats on topics such as Energy Efficiency Policy Strategies from Around the World; Growing Economies in a Carbon-Constrained World: The Role of Energy Efficiency in the Business and Industrial Sectors; and What Is the Real Potential for Energy Efficiency? Contrasting Perspectives.
Not a lot of residential weatherization-related technologies, but having an apartment in Paris for three weeks allowed me to experience the small footprint, and it was unreal to step out into the streets and see how life goes on in one of the truly amazing cities in Europe.
During my exploration of Paris, I kept noticing billboards advertising “foire de Paris.” Come to find out, this was the Paris home show. This event welcomes about 500,000 visitors every year to see over 2,500 exhibitions; it has been taking place for over 106 years. You can buy or be sold anything—furniture, housewares, kitchens, bedrooms, tools, organic food, hi-tech music, vacations, cars, even swimming pools.
Over 500 inventions were on display in Pavilion 7, where inventors were competing for the Concours Lépine. This prize, first awarded in 1901, has recognized the inventors of Braille, the artificial heart, the steam iron, the ballpoint pen, the automatic parachute, and the dishwasher, to name a few.
My first stop was the 25,000 m2 Salon de Construction et Renovation, with over 250 exhibitors. It was overwhelming. I managed to stumble through a wide assortment of displays of appliances, building materials, efficient heating systems, and renewable-energy systems, all in French. In fact, I might have been the only American in the whole hall. I especially enjoyed looking at the European kitchen appliances, which were consistently efficient and elegantly designed.
The following spring, I returned to Paris and took the train to London to attend Ecobuild. With an attendance of more than 40,000 people, this six-year-old exposition, held March 2–4, 2010, at Earls Court, accomplished no small feat. It offered free admission, over 1,000 exhibitors of building products and services, and more than 100 seminars. Topics included government policy and regulation updates, renewable energy, water efficiency, green infrastructure, urban planning, landscaping, basic technology of energy-efficient systems, and much more.
Live demonstrations, such as solar PV installation and insulation installation, attracted the crowds. A highly visited attraction was the University of Nottingham’s 74 m2 (796 ft2) energy-efficient home, which was designed to Passive House building standards. Also present were product manufacturers from all of Europe, as well as China and Canada, touting wares ranging from engineered timber and interior finishes to prefabricated houses designed to Passive House standards. A couple of products in particular caught my attention. The first was Tradical Hemcrete. Made from hemp and lime as a hemp binder, in timber frame construction, it provides the wall form, the racking strength and the insulation. In steel and concrete framed buildings, it provides the wall form and insulation in one monolithic product. Hemcrete works as both insulation and thermal mass. Even though its R-value is relatively low, say 1 per inch, it seems to perform much like adobe or rammed earth. The second was Ecosheet, a green and lightweight alternative to 4-foot x 8-foot plywood sheets. This product is made from 100% recycled plastic and can be fully recycled.
The Europeans have quite a different mind-set when it comes to energy efficiency than do Americans. I first noticed this last winter, while I was living with a French family. First of all, the south of France is a cold place from November through February, but you live accordingly. I stayed in a 1960s mostly masonry, single-story, flat-roofed home, a modern house by European standards. You feel, accept, and adapt to the changing seasons. The house was heated with an oil-fired boiler, located in a separate building. It had a forced-air duct system with a water-to-air heat exchanger. The boiler-heated water was delivered via utilidor. Fuel oil was costing €1.40 a liter (US$7.20 per gallon). The thermostat was mostly set at 18ºC (64.4ºF) during the day, and less during the night. We all wore sweaters and house shoes with thick socks.
Blankets were kept around to bundle up in, and there were fires. On cold nights, the ritual was to build a fire in the chimney, the French name for an open fireplace. The damper was a chimney-top model. The wood was gathered locally. It was Europe; they’ve been building fires indoors for centuries. We sat by the fire for an aperitif, for reading, or for music. We would even roast chestnuts over the flames, old school. The hearth was still the hearth, the center of activity in the home in winter. I thought how different it would be sitting next to a high-tech sealed-combustion boiler. A carbon trade-off: fireplaces. I know how inefficient a fireplace is, but we all know how comforting being next to a radiant fire is, too. During the night, we slept under thick down.
My hosts were very aware of the need to conserve resources—heat turned down, curtains and shutters drawn. Lights were turned off when not needed, water was never left to run. I was busted once for letting the water run while brushing my teeth.
One thing I noticed in the south of France was the use of passive ventilation. There were usually two small sidewall vents—one low and one high—in the bathrooms and kitchens. These vents could sometimes be closed, but not always. Also, all the windows were opened every morning, the bedding was hung out to air dry, and the house was aired out. Although passive ventilation is not an exact science and involves active participation of occupants, it is effective and has become part of the culture.
For more information about the EU energy label, visit www.energy.eu.
For free access to the EU law, go to www.eur-lex.europa.eu.
To learn more about Germany’s equivalent to DOE, go to www.dena.de.
Read more about energy-efficient windows at the Danish Energy Agency web site, www.ens.dk/en-US/ConsumptionAndSavings/Buildings/Windows.
More information on Tradical Hemcrete can be found at www.lhoist.co.uk/tradical.
Across the Atlantic
Energy efficiency continues to be a popular topic on both sides of the Atlantic. Resources are expensive. Carbon reduction is in the news. The technologies are available, but they still need to be paid for. Europe has not implemented weatherization programs as extensively as we have in the United States. The EU is pushing the market and industry to provide more- efficient products. Both the U.S. government and the EU have had success with energy labeling. There are tax incentives, and consumers on both sides of the Atlantic are becoming more aware of the need to be more efficient. The Europeans install more boilers and windows in retrofit than we do; we address the building shell and airtightness more than they do. But it’s arduous and challenging to apply the technology at the level needed. This is proven by both sides’ failure to meet projections, such as the EU’s 2020 plan. The economics of efficiency make more sense than ever in the current economic downturn. The carbon footprint continues to grow globally by leaps and bounds (45% between 1990 and 2010).
There is much to share between countries east and west. We all need to analyze and benchmark buildings for efficiency improvements. We all need to educate both the consumer and the installer. We all need to apply the energy-efficient technologies. To do so makes economic and environmental sense.
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