Keep the building warm in the winter and cool in the summer. Comfortable with little to no utility bill / fossil fuel.

This increases both psychological and physiological comfort.

Both the International Building Code and the International Residential Code have requirements for maintaining a minimum temperature in buildings. They do not have requirements for a maximum temperature in buildings though there are ventilation system requirements and there are reasonable standards for comfort.

“All design projects should engage the environment in a way that dramatically reduces or eliminates the need for fossil fuel.”
The 2010 Imperative, Edward Mazria,AIA, Founder of Architecture 2030

World Energy Use by SectorBuildings use about 48% of all electrical energy generated by  humanity. Of that 48%, about 40% is for operating the buildings (heating, cooling, lighting, computers, etc.) and about 10% is for the construction (creating materials, transportation, design and construction).

Buildings do not have to use fossil fuels. Humanity has learned how to design buildings that are super energy-efficient that zero-energy buildings can now be built. The small amount of energy buildings still need can be supplied by renewable sources such as photovoltaic (solar) and wind modules.

 Characteristics of a zero-energy home.

  • Correct Orientation.
  • Form as compact as appropriate for the climate and function.
  • Appropriate colors of surfaces.
  • Super-insulated walls, roof and the floor where appropriate.
  • Appropriate and Intensive use of thermal mass.
  • Air-tight construction with appropriate ventilation.
  • High-performance, properly oriented windows.
  • Windows fully shaded in the summer.
  • Passive Solar with Active backup space heating.
  • Passive Solar with Active backup domestic hot water.
  • High-efficiency appliances.
  • High-efficiency lighting.
  • High-efficiency heating and cooling equipment (if any).
  • Photovoltaic, wind energy, other renewable source.

In the United States the energy for cooling is increasing as more people can afford it and as more people move to the South.

Because most people live in hot climates and because the number of people who can afford air conditioners is increasing rapidly, the energy needed for cooling is increasing exponentially. Thus, heat avoidance strategies such as shading will dominate future world architecture.

Buildings are designed for people, and those people are trying to accomplish a task – whether it’s raising a family, running an office, or manufacturing a product. The building needs to keep people comfortable, efficient, healthy, and safe as they set about their task.

Energy-efficient buildings are only effective when the occupants of the buildings are comfortable. If they are not comfortable, then they will take alternative means of heating or cooling a space such as space heaters or window-mounted air conditioners that could be substantially worse than typical Heating, Ventilation and Air Conditioning (HVAC) systems.

When people are dissatisfied with their thermal environment, not only is it a potential health hazard, it also impacts on their ability to function effectively, their satisfaction at work, the likelihood they will remain a customer and so on.

Textbook Cover 3D Heating & Cooling passive houseHeating & Cooling Book – $50 digital download

($50 until October 31, get it now. normally $150.)

242 pages with graphs, charts, images and diagrams explaining ALL aspects of heating and cooling buildings. Residential buildings and Commercial buildings and Government buildings. This is the pathway to total and complete sustainability, way beyond LEED.

  • Thermal Comfort
  • Adaptive Comfort
  • Codes and regulations relative to Comfort
  • Passive Solar
  • What is a Passive Building?
  • Climate & Culture Physics & Humanity
  • Insulation
  • How to Install Insulation
  • Thermal Mass
  • Cooling
  • The Perfect Wall
  • How to Install Thermal Mass
  • Thermal Envelope
  • Energy Efficient Windows

click here for the complete Table of Contents.

Sustainable designs for cold climates

The IBC requires that interior spaces that are intended for human occupancy need to be able to maintain a minimum interior temperature of 68 degrees at a point 3 feet above the floor. This can be done actively, passively or with a combination of the two methods. The system design is based on the design heating day for the location.

The IRC is slightly more forgiving, it says that the 68 degrees must be maintained at a point 3 feet above the floor and 2 feet from the exterior wall. You only have to provide the system where winter design temperatures are below 60 degrees. Portable space heaters can’t be used to meet the requirement

sustainable designs for hot climates

A building must be warm in the winter and cool in the summer.

Humans have been heating their buildings with various resources over the centuries. The sun is the strongest and most consistent source of heat. It is also free, abundant and clean.

Passive House Diagram

There is plenty of heat coming from the sun. By directing the building toward the sun and having larger windows facing the sun, heat gain from the sun, called solar gain can be maximized. The maximized heat that is now coming into the building from the sun can be stored within thermal mass. This Thermal mass can be any earth-type material. Dirt, rock, stone, liquids such as water, beer, etc.

By adhering to and utilizing design directives as well as small, subtle ones, a building can stay warm in the winter and cool in the summer with no fossil fuels, no machines and no direct cost. The design directives come from the physics of the planet and the environmental characteristics of the local building site. Taking into account all environmental aspects of the building site will allow the building to maximize its performance potential. For example. is there full horizon to horizon sun? Are there any tall trees blocking the heat from the sun to the building? At what latitude is the local building site?


Passive Solar

In ‘passive solar’ building design, windows, walls, and floors are made to have certain affects and qualities throughout the year, specifically the winter and summer months.

This is called ‘passive solar design’ because, unlike ‘active solar’ heating systems, it does not involve the use of mechanical and electrical devices. Everything ‘responds’ to an input of energy, this is ‘passive’.

“Passive solar” refers to a system that collects, stores, and redistributes solar energy without the use of complex mechanical controllers. It functions by relying on an integrated approach to design, where the basic building elements, such as windows, walls, and doors, have many different functions. For example, the walls hold up the roof and keep out the weather and also act as heat-storage, heat-radiating and heat-sink elements. These various components of a building simultaneously satisfy architectural, structural, energy and comfort requirements.

Passive Solar System TypesEvery passive solar heating system has at least two elements: a collector consisting of south-facing (equator-facing) glazing and an energy-storage element that usually consists of thermal mass, such as dirt, rock or water.

Depending on the relationship of these two elements, there are several possible types of passive solar systems.

– Direct gain
– Sunspace / Greenhouse (isolated gain)
– Thermosiphon / Trombe wall (indirect gain)

It is important to realize that a passive solar system does more than just heat the building. Most importantly, it provides security because the temperature inside a passive solar building will be much higher than a standard building in case of an extended power failure in the winter. Thus, passive solar is part of resilient design. Passive solar also provides daylighting and a healthy exposure to sunlight. Lastly, the mass needed to store heat can usually also be used for passive cooling in the summer.

The key to designing a passive solar building is to best take advantage of the local climate performing an accurate site analysis. Elements to be considered include window placement and size, and glazing type, thermal insulation, thermal mass, and shading. Passive solar design techniques can be applied easily to new buildings, but existing buildings can be adapted or “retrofitted”.

Surface Color & Solar Gain

The U.S. Environmental Protection Agency (EPA) says that for low-rise commercial buildings, the heat gain through the roof is about 50 percent of the heat gain for the entire building. This heat gain can be reduced not only by using more insulation but also by reflecting the sun’s radiation. The American Society of Heating, Refrigeration, and Air-conditioning Engineers (ASHRAE) states that the heat gain through a white roof is half of that of a black roof, and the heat gain through a white wall is two-thirds that of a black wall. Thus, in hot cli- mates, the walls should have a light color and the roof should be white.

Solar reflectivity, which is also known by the term “albedo,” is a number that indicates how much of the solar radiation is reflected from a surface. An albedo of 0 indicates that no sunlight is reflected or that all sunlight is absorbed, while an albedo of 1 indicates that all sunlight is reflected. The color white has the highest solar reflectivity with an albedo of about 0.9 (90 percent is reflected) if it is fresh, clean, and glossy. Clearly then, the most sustainable buildings would have white roofs and appropriately utilize the colors with an awareness of these aspects.

White is the Greenest Color

solar cool roof vs conventional roofWhen it comes to solar-responsive design, choosing white can be the easiest and biggest bang for your buck. Selecting white design elements can save a lot of energy, resulting in saving money and being more efficient and comfortable.

White roofs dramatically reduce overheating in both buildings and cities. A white roof will reflect much of the sun’s energy, while a dark roof absorbs most of the sunlight and turns it into heat.

A dark roof can get more than 60°F (33°C) hotter than a white roof, significantly heating both the building and the outdoor air. As a result, buildings get heated twice by their dark roofs — once directly through the roofs, and secondly by the increased air temperature of the neighborhood. Cities can be as much as 16°F (9°C) warmer than the surrounding rural areas due to the extra absorption of dark roofs and pavements and the lack of trees. This “heat island effect” also increases pollution levels in cities.

“Rapid deployment of cool materials represents one of the largest and most cost-effective opportunities we have to improve health and strengthen security.” 
— U.S. Secretary of Energy Steven Chu

White buildings can also reduce the energy required for lighting a building. White ceilings and interior walls make electric lighting more efficient, and white roofs and exterior walls can make daylighting more efficient in urban areas. Because daylight enters windows from the sky, most of the light ends up illuminating only the indoor spaces near the windows. On the other hand, much of the light reflected from white walls and the roofs of lower buildings enters windows from below, thereby illuminating the ceiling, which generates better lighting and also sends it farther indoors. White exterior walls also improve nighttime lighting by reflecting, rather than absorbing, street and area lighting.

Climate & Culture: Physics & Humanity

“The earth provides enough to satisfy every man’s need, but not enough to satisfy every man’s greed.”
– Mahatma Gandhi 

We must begin by taking note of the countries and climates in which homes are to be built if our designs for them are to be correct.
One type of house seems appropriate for Egypt, another for Spain… one still different for Rome… and Africa… and China…
It is obvious that design for homes ought to conform to diversities of climate and culture.
– The Ten Books on Architecture, Vitruvius  Architect, first century b.c. 

Climate (physics)
The climate, or average weather, is primarily a function of the sun. The word “climate” comes from the Greek klima, which means the slope of the earth in respect to the sun. The Greeks realized that climate is largely a function of sun angles (latitude) and, therefore, they divided the world into the tropic, temperate, and arctic zones.

The atmosphere is a giant heat machine fueled by the sun. Since the atmosphere is largely transparent to solar energy, the main heating of the air occurs at the earth’s surface. As the air is heated, it rises and creates a low-pressure area at ground level. Since the surface of the earth is not heated equally, there will be both relatively low and high pressure areas with wind as a  consequence. Combined with mountain, trees, lakes, jungle, etc., we have different climates. There are even micro-climates.

Culture (humanity)

As designers, builders, educators and laborers of modern times, we must be urban anthropologists capable of understanding the big and little nuances of cultural divergencies. The buildings of today naturally become cultural melting pots. We are charged with working more closely with clients to harness the cultural environment of those using the space. It is essential that spaces speak well to different audiences and that they do not inadvertently offend any of them. We have a great responsibility to the public.


insulation passive house no air leaksThermal insulation in buildings is an important factor to achieving comfort. Insulation reduces unwanted heat loss or heat gain and can decrease the energy demands of heating and cooling systems. Thermal Insulation does not necessarily deal with issues of adequate ventilation and may or may not affect the level of sound insulation. In general, “the more insulation the better” is a good principle to start with.

There is, of course, a limit to  how much should be used. The law of diminishing returns says that every time you double the amount of insulation, you cut the heat loss in half. This is great the first few times as the heat loss goes from 1 to 1⁄2 to 1⁄4, etc. Unfortunately, the cost keeps up with the thickness of insulation, while the heat loss decreases by ever smaller amounts (e.g., from 1∕32 to 1∕64 to 1∕128, etc.). However, this simplistic approach to building economics has done much damage. A more realistic approach is to see how the cost of the whole building changes as more insulation is used. As Amory Lovins says, “You can tunnel through the cost barrier.” As more insulation is used, the heating and cooling systems get smaller and less expensive. In many climates, super-insulation can eliminate the heating system altogether, and in some climates it also eliminates the cooling system. Large amounts of insulation can be less expensive than small amounts even for the initial costs.

Large amounts of insulation also provide a passive security system. When there is a power failure in the winter in a super-insulated building, the temperature indoors will drop less, and more slowly, than in a conventional building. It is surprising that in a world where people crave security, they don’t make their homes more secure. However, there is growing interest in making our buildings and communities more resilient by the way they are designed and built. Furthermore, since future energy sup- plies and cost are uncertain, it is wise to be conservative and to use as much insulation as possible.

Insulation goes everywhere so there are no gaps anywhere. 

Most conventional buildings only use insulation and do not use thermal mass. All buildings should use both insulation and thermal mass. Thermal Mass on the inside of the wall and insulation on the outside of the wall. See below ‘The Perfect Wall’.

The effectiveness of insulation is evaluated by its R-value, of which there are two – metric (SI) and US customary, the former being 0.176 times the latter. For attics, it is recommended that it should be at least R-38 (US customary, R-6.7 metric). However, an R-value does not take into account the quality of construction or local environmental factors for each building. Construction quality issues include inadequate vapor barriers, and problems with draft-proofing. In addition, the properties and density of the insulation material itself is critical.

Thermal Mass

Thermal mass is a property of the mass of a building which enables it to store heat, providing “inertia” against temperature fluctuations. A lot of heat energy is required to change the temperature of high density materials like concrete, bricks, mud, water, compacted dirt and tiles. Appropriate use of thermal mass throughout the building can make a big difference to comfort and heating & cooling bills.

For example, when outside temperatures are fluctuating throughout the day, a large thermal mass within the insulated portion of a house can serve to “flatten out” the daily temperature fluctuations, since the thermal mass will absorb thermal energy when the surroundings are higher in temperature than the mass, and give thermal energy back when the surroundings are cooler, without reaching thermal equilibrium. This is very different from a material’s insulative value, which reduces a building’s thermal conductivity, allowing it to be heated or cooled relatively separate from the outside, or even just retain the occupants’ thermal energy longer.

sustainable green buildings

Thermal mass vastly improves building comfort anywhere that experiences these types of daily temperature fluctuations—both in winter as well as in summer. When used well and combined with passive solar design, all heating and cooling requirements throughout the year can be met This results in a comfortable building which requires no monthly bills, no fossil fuels, no moving parts and will never stop. In addition to this, active heating and cooling systems can be used. Thermal mass will simply majorly reduce the energy use when compared to buildings that do not properly combine thermal mass and passive solar design.

Poor use of thermal mass can exacerbate the worst extremes of the climate and can be a huge energy and comfort liability. It can radiate heat to you all night as you attempt to sleep during a summer heatwave or absorb all the heat you produce on a winter night.

To be effective, thermal mass must be integrated with sound passive design techniques. This means having appropriate areas of glazing facing appropriate directions with appropriate levels of shading, ventilation, insulation and thermal mass. The ideal wall has insulation on the exterior of the wall and the thermal mass on the interior of the wall. The thermal mass is also usually the strength/structure of the building.

Thermal Envelope

The thermal envelope defines the conditioned or living space in a building. The attic or basement may or may not be included in this area. Reducing airflow from inside to outside can help to reduce convective heat transfer significantly.

Create an efficient thermal envelope to minimize the heat loss in winter and heat gain in the summer.

Suppose we wanted to keep a certain bucket full of water. Our common sense would have us repair the leaks, at least the major ones, rather than just refilling the bucket continuously. Yet with regard to energy, we usually keep a leaky building warm by pouring in more heat rather than patching the leaks.

Perhaps if we could see the energy leaking out, we would plug the leaks. Fortunately, we can see the holes in the thermal envelope with thermography, and it is very effective in convincing people to upgrade their buildings. In a thermogram of the exterior of a building, hot and cold areas are shown in different shades of gray or colors.

From experience, we know that comfort can be increased if the proper conservation techniques are used. For example, indoor comfort increases dramatically when insulation is added to the walls, the ceiling, and especially the windows. We can be uncomfortably cold even when the thermostat is set at 80°F (27°C). The addition of ceiling insulation and insulating drapes over the windows now allows a thermostat setting of 70°F (21°C) to provide  complete thermal comfort. Thus, insulation not only reduced energy consumption, it also increased thermal comfort by increasing the mean radiant temperature of the space.

It is not only possible but also more likely to have a higher standard of living through energy efficiency. 

After all, higher efficiency will enable us to meet the needs of heating, cooling, and lighting at less cost, leaving more money for other needs.

The less natural airflow into a building, the more mechanical ventilation will be required to support human comfort. High humidity can be a significant issue associated with lack of airflow, causing condensation, rotting construction materials, and encouraging microbial growth such as mould and bacteria. Moisture can also drastically reduce the effectiveness of insulation by creating a thermal bridge. Air exchange systems can be actively or passively incorporated to address these problems.

Textbook Cover 3D Heating & Cooling passive houseHeating & Cooling Book – $50 digital download – Table of Contents

($50 until October 31, get it now. normally $150.)

Heating & Cooling the building 3

Thermal Comfort 9

Adaptive Comfort 10

Codes and Regulations relative to Comfort 12

Passive Solar 15

Heat Flow 18

Radiant Energy 19

Passive Solar Energy Gain 20

Direct Solar Gain Systems 22

The Greenhouse Effect 24

Sunspaces / Greenhouses 26

Thermosiphon (Convective-Loop System) 28

Trombe Walls 30

Surface Color & Solar Gain 33

Drawing Sun Beams on Best Dates 40

Review: Passive Solar 43

What is a Passive Building? 45

The Principles of a Passive Building 46

History: ’PassiveHaus’ > ‘Passive House’ > passive building 48

Climate & Culture: Physics & Humanity 49

Tropical Climate: Hot / Humid 50

Temperature Climate: Warm / Humid 62

Temperate / Upland Climate: Dry / Cool 70

Arid Climate: Dry Hot / Cold 74

Local Anthropologically and Culturally Aware Design 86

Plant Species and their Characteristics 89

Insulation 90

R-Value 92

U-Factor / U-Value 92

Deterioration 92

Air Leaks and Insulation 93

How Insulation Works 98

Total R-Values for New Conventional Houses 99

Typical R-values 100

Footing / Foundation / Slab Insulation 102

Frost Line 107

Frost heaving 108

Types of Insulation 111

Advantages of cellulose insulation 120

How to Install Insulation 124

Thermal Wrap: Turbo Charge your Green Building 125

Batts 129

Rigid/Panels 132

Retrofit a building with Rigid Insulation panels 143

Thermal Mass 146

How thermal mass works 148

Using thermal mass effectively 149

Choose the right amount of thermal mass 150

Where to locate thermal mass 152

Where not to locate thermal mass 153

Typical applications 154

Heat Sink 155

Glass to Thermal Mass ratios for different climates 156

Air Volume to Thermal Mass Volume Ratio 160

Thermal mass properties 162

Multi-story buildings 166

Earth Sheltering 166

Thermal mass checklist 170

Cooling 172

Four Types of Passive Cooling Systems 172

Ventilation 181

Shading 185

Ecological Impact of Earthships 187

The Perfect Wall 191

How to Install Thermal Mass 193

Rammed Earth in Tires 193

Slip Form: Stone Masonry & Concrete 194

Adobe Brick Walls 203

Water as Thermal Mass: Liquid Thermal Mass 210

Thermal Envelope 214

Heat Loss 218

Heat Gain 220

Moisture Control 222

Vapor Barriers 224

Infiltration & Ventilation: Air Sealing 226

Energy Efficient Windows 230

Improving the energy efficiency of existing windows 232





Selection 236

Window Boxes 237


Thermographic Inspection 241