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The HVAC Blog is the place for conversation and discussion about building HVAC control, energy conservation and efficiency, heating, and cooling. Here, you'll find everything from application ideas, to news and industry trends, to hot topics and cutting edge innovations.

The History of Heating Houses

Posted February 19, 2013 12:00 AM by Chelsey H

I grew up in the country with a wood-burning furnace to heat the house. I think everyone in my neighborhood had one because as soon as you go off the highway for my town, everything smelled like burning wood. It's such a cozy, comforting smell. Wood has been used to heat dwellings dating back a million years. The transformation from open fire to the modern wood stove is explained in the story below.

What we would now consider a campfire was once all people had to heat the house, cook, heating water to wash, etc. The earliest evidence of a controlled fire can be found in South Africa and dates back a million years, but the first evidence of a pit of hearth was found in Israel from 750,000 years ago. This fire burned grain, bones, seed, and wood. Today, campfires are used for survival, but more commonly just for fun.

Image Credit: Inventors Digest

Open fireplaces provide ambience and romance. Although they are considered inefficient and dangerous today, open fireplaces were the standard heat sources for thousands of years. The most primitive form of a fireplace may be seen in the Orkeny and Shetland Islands between the UK and Norway. These fireplaces consisted of a central hearth and a rising lump of stone, slightly hollowed in one face to form a backing to the fire. Again the fireplace was used for almost everything in daily life. They were often put in the center of the room and smoke (a least a little bit of it) leaked out from the windows (no glass) and by holes which were poked in the walls or roof. In other places in the world, such as Mexico, devices called chimeneas were being used by Mexican tribesmen to provide heat for their family. The bulbous design, which included a "chimney" with a lid, was intended to keep rain off the fire and keep everyone warm with minimal fuel. What's weird is that some Romans warmed their houses using interior pipes laid under the floors and used flues to pipe the smoke outside, but somehow all these ideas were lost with the fall of the Roman Empire. And it wasn't until the 13th Century that there was advancement on the fireplace - the chimney.

Around 1066, the fireplaces were moved into a niche in the wall and holes were poked into the exterior wall to allow the smoke to escape. Eventually flues and stone hoods were installed to facilitate ventilation. Many homes still used a louver on their roof, which is an opening with a raised area that would allow smoke from a ventral fire to escape while preventing water or debris from coming inside. When coal became popular it became important to remove the coal smoke and more sophisticated ventilation, in the form of the chimney, was developed.

Elaborate Tudor brickwork chimneys at Hampton Court Palace. Image Credit: Apartmenttherapy.com

Good ol' Benjamin Franklin can be credited with founding what is now the modern day stove. In 1642, a Massachusetts foundry constructed the first box of cast iron plates with the intention of burning wood inside. Over 100 years later, Franklin created the Franklin stove with a hollow baffle at the rear with the intention of increasing the heat and reducing the amount of smoke that would circulate around the room. The U-shaped flue in a Franklin stove draws hot gases from the fire into a hollow baffle. This heats up cool air inside the baffle and then expels it into the room via vents near the top.

Image Credit: Popular Mechanics

At the end of the 18th Century, Benjamin Thompson suggested that chimneys feature a slanted fireback and adjustable flue damper. This became the norm for stoves in large estates and working kitchens in stately homes. This was eventually scaled down to fit in more homes by Philo Stewart, who patented his Oberlin stove in 1834. It was a totally cast-iron stove and while the designs have changed to compensate for aesthetics and increase efficiency, the basic workings have remained the same. The potbelly stove is probably the most iconic older stove design. It first appeared around 1860 and was used in train stations, cabooses, and hunting lodges. The firebox was enclosed and was able to release a lot of heat.

In the late 19th Century wood-fire cookstove systems became popular. They featured a large cast-iron surface and an elegantly enameled oven. The cookstoves were used for cooking food, warm water, and heat homes. They are still produced but have lost popularity due to the high amount of fuel required. Masonry stoves rely on fast, hot fires to store heat energy in the stove's large masonry, ceramic, or plaster thermal mass which is then released gradually over hours or even days. They have complex heat-exchange passages and are often referred to as Kachelofen (their German name).

One of the biggest weaknesses of wood stoves in the past is that they leaked and let in air, which means the fire would burn out in an hour or two. The Airtight Stove of the 1970s and '80s allowed the user to control the airflow, and therefore the burn. The embers would glow hot for eight hours or more, but the slower burn resulted in smoky stoves that were unnecessarily pollutant. Modern stoves are highly efficient catalytic and noncatalytic airtight stoves which aim to eliminate emissions and increase efficiency through complete combustion of the wood fuel. Noncatalytic stoves feature a damper that directs smoke and creosote into a secondary combustion chamber for reignition. Catalytic combustors in stoves are similar to those in cars.

Image Credit: Popular Mechanics

My family's house uses an indoor wood furnace and I love it, even though it does require a little more work (stacking wood was torture when I was little when I lived at home.) It keeps the house cozy warm and I love the smell of wood. Indoor wood furnaces are designed to vent all the smoke and exhaust outside through a chimney. They are used to heat water circulated into a radiator that is attached to ductwork throughout the house. A blower is then used to transfer the heat into the air.

I couldn't image having a fireplace in the middle of my living room, but I'm sure some people can't even imagine loading wood into a furnace to heat their house today like I do. All I know is that I'm glad for chimneys.

What do you use to keep your house warm? Keep Warm!

Resources

Quick History: The Evolution of the Chimney

The Evolution of the Fireplace

The History of the Modern Woodburning Stove

Know Your Wood-Burning Stoves

14 comments; last comment on 02/22/2013
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Are Incentives Worth the Investment?

Posted January 11, 2012 7:06 AM

There's lots of pressure to be more efficient and environmentally friendly. With that in mind, governments are offering plenty of financial incentives to businesses to install solar heating and passive cooling systems. Do these incentives make the investment worth it? What obstacles or reasons do you see that might keep a business from upgrading, even when there's the promise of government support?

The preceding article is a "sneak peek" from HVAC, a newsletter from GlobalSpec. To stay up-to-date and informed on industry trends, products, and technologies, subscribe to HVAC today.

11 comments; last comment on 10/31/2012
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How Will New HVAC Employees be Found?

Posted December 14, 2011 8:05 AM

As more and more members of the baby boomer generation retire, the need for trained workers in the HVAC industry continues to grow. So how does the industry recruit those workers? Some employers are trying unconventional routes, like using Twitter and YouTube to attract young talent. Is this the way to go? Or do you have a different recommendation for where and how to find and train the skilled HVAC employees of tomorrow?

The preceding article is a "sneak peek" from HVAC, a newsletter from GlobalSpec. To stay up-to-date and informed on industry trends, products, and technologies, subscribe to HVAC today.

10 comments; last comment on 07/14/2012
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Just How Efficient Can We Get?

Posted November 09, 2011 7:21 AM

Many say it's impractical to try and get to 100% efficiency from forced-air furnaces. However, numbers like that would be worth big bragging rights for the company that manages it. What do you think? Should companies continue to push for even more efficiency in furnaces for homes and businesses?

The preceding article is a "sneak peek" from HVAC, a newsletter from GlobalSpec. To stay up-to-date and informed on industry trends, products, and technologies, subscribe to HVAC today.

6 comments; last comment on 11/12/2011
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How to Handle HVAC in Extreme Heat?

Posted October 12, 2011 8:18 AM

We hear a lot of talk about extreme weather conditions lately, particularly heat waves and droughts in the Southern U.S. and other similar climes. There's also a lot of talk about cutting fuel use. With that in mind, are there innovative solutions for low-cost HVAC in very hot environments that you think should be implemented, but aren't?

The preceding article is a "sneak peek" from HVAC, a newsletter from GlobalSpec. To stay up-to-date and informed on industry trends, products, and technologies, subscribe to HVAC today.

11 comments; last comment on 11/28/2011
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Should AC Thieves Face Stronger Penalties?

Posted September 14, 2011 10:11 AM

In August, the Associated Press reported that the heat wave in Texas was made worse by thieves stealing air-conditioning units. The thieves are looking to sell copper and other metal from the units, but stealing them is more than just a pain for owners; it puts their health and safety at risk. With that in mind, should thieves of air-conditioning units face harsher penalties if they are caught stealing during a heat wave?

The preceding article is a "sneak peek" from HVAC, a newsletter from GlobalSpec. To stay up-to-date and informed on industry trends, products, and technologies, subscribe to HVAC today.

77 comments; last comment on 11/14/2011
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