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Heat Management | Homebuilding in the Senderos

Building a home suited to its environment, its neighborhood, and the unique needs of its homeowners requires careful consideration from start to finish. 

Beginning with site study, moving through design, to construction, and finally to homeowner education, building a home is part art, part design puzzle, and part engineering challenge. 

As part of our ongoing interviews with Managing Partner Curtis Peart, we’re taking a deep dive into some of the specific challenges that arise during the homebuilding process, and how our team tackles them in Senderos. 

For this week, we discuss one of the most pressing considerations of any home in the tropics — heat management — including why it’s so important, the types of heat, some cooling strategies, and how Senderos is working on the cutting edge in this aspect of homebuilding.

Why Heat Management Is Important

Managing heat is important for two key aspects of the home: the comfort of the residents, as well as the home’s energy efficiency. 

One of the most pressing uses of energy in a home is its climate control, and intelligent design can be the difference between a home that’s naturally comfortable and enjoyable to be in versus a home that is frequently uncomfortable and can be expensive to maintain.

One benefit of the tropics is that the temperature stays relatively the same year round, so homes only have to be built to stay cool. In contrast, more temperate regions have to deal with both heating and cooling depending on the time of year, making heat management more complicated.

For homes in Senderos, this means that designers can focus on two main areas: preventing the accumulation of heat in the home, and cooling the home by shedding existing heat. You can get a little more creative and innovative that way, compared to having to keep it cool in the summer and warm in the winter.”

Thanks to Guanacaste’s warm climate, designers can focus on integrated cooling that works year-round

The Types of Heat

There are three main types of heat transfer: 

  • Convection, in which hot or cool air moves into an area and either withdraws or adds heat. 
  • Conduction, in which heat is transferred directly from a hot surface to a colder surface.
  • Radiation, in which something that has high heat, transfers its energy to the objects around it (though they are not directly touching) 

The most common form of heat that home designers have to deal with is radiation, primarily from the sun, which is stored in the home and the surrounding materials throughout the day. 

Second most common is convection, primarily through wind cooling and air-conditioning, which are the most common ways to fine tune your heat control. 

Conduction doesn’t affect the overall heat of the home as much as the other forms of heat transfer, but it can still be crucial to your experience, especially in outdoor surfaces. For example, choosing outdoor materials that stay cool during the heat of the day can be the difference between a refreshing pool terrace and an inhospitably hot outdoor deck.

How Different Forms of Heat Shape Your Experience

“A good story that shows this. I remember getting out of the car in a parking lot at Hacienda Guachipelin before a mountain bike ride, and just being blazing hot. But then I got on my bike and I rode maybe a few hundred meters down to a waterfall, and I was darn near cold. 

Let’s break down some of the forces that contribute to that change — and you start to see how you can take this combination of little things and create your own, excellently managed microclimate.

In the parking lot you have no shade, so the sun is radiating heat directly onto you. You’re also on the pavement, which is a thermal mass that stores heat, and is also radiating heat onto you. There’s no breeze either, so you have no convection cooling, and the physical heat of the pavement and cars actually directly hits you through your feet. 

Now think about that waterfall. First off, you’re shaded, so you’ve subtracted the direct heat from the sun. Then you have a body of water, which is a negative thermal mass, so it removes heat from the surrounding area. You have the cool airflow coming from the river, which cools you off through convection, and then mist from the water and the cooler materials (like grass) reduce the effect of conduction as well. 

We prioritize the same things in selecting home materials and the home design, as we try to create our own little microclimates that are a pleasure to be in, even when the surrounding area can be very warm. 

We choose materials that reflect heat, rather than absorbing it. Bright tiles, woods, even grass — they don’t accumulate heat, while other materials — asphalt, or a black roof — will make it nearly impossible to cool things down.

If you can win that battle with radiant heat through design, before you even get into the A/C or climate control, or picking tiles that won’t conduct heat directly, you can make your job a lot easier.”

Radiant heat is also why it feels cooler right on the shoreline, when it might feel much warmer just a short ways away.

Preventing Accumulation of Radiant Heat | Types of Cooling

Through radiant heat, the sun is going to heat up different areas and parts of your home throughout the day, which makes it important to avoid heat sinks — materials that absorb and store heat — and include design choices that provide shade and reflect heat.

A well-insulated home in this context doesn’t always mean thick walls and protection from the elements. 

Instead, these homes make use of brighter colors that reflect light, less-dense materials that don’t accumulate heat, and landscaping like grass, trees, and native plants that provide shade and don’t collect excess warmth, while also adding natural beauty. 

*Our team in Senderos has also begun to innovate with radiant cooling, a relatively new concept that we’ll touch on later in the article

“There are some things almost everyone knows — like the fact that you rarely want to build a dense, heat-absorbing roof if you’re looking for any chance at keeping a home cool. But there are some other mistakes that we see made frequently in our region. 

For example, some people design these heavy block homes, which are intended to protect from the heat, but actually end up creating a massive heat sink that works essentially like a pizza oven. Needless to say, that makes it a bit harder to keep things cool.”

A Common Challenge | Considering Views

One of the biggest challenges faced by designers in Guanacaste is balance of expansive, desirable views vs heat control. 

“In Guanacaste, and especially in Senderos, we have some fantastic ocean-facing views, which immediately makes it desirable to have western-facing glass. 

But you have to be very careful there, because large faces of unshielded glass have a tendency to build up heat. The sun’s radiation heats up everything inside, but then the glass walls or windows don’t let the heat back out, and all of a sudden your living room works just like a greenhouse would. 

So you’re faced with the challenge: how do you achieve the views that you come here to build without building a greenhouse or an oven?

And it’s possible. You can get special glass that reflects radiant heat, or you can design protection into the home so it’s well shaded except for at those peak sunset times when you won’t accumulate heat. The key is just being smart about the design. 

Senderos is home to some truly spectacular views. It’s up to the designer to embrace this astounding natural beauty without sacrificing comfort.

Wind Cooling and Air Conditioning | Active and Passive Convection Cooling

Though managing radiant heat often dictates the overall heat of a home, convection cooling is perhaps the most common tool for fine tuning the climate control within a home. 

Air conditioning is one of the most ubiquitous examples, in which the A/C unit produces cold air, which is blown out into the room, the cool air then absorbs heat from the interior area through convection. 

Another method that is frequently used in Costa Rica is wind cooling, by allowing ventilation through the home. 

Breezes actually work slightly differently than air-conditioning in that the breezes in question aren’t actually much colder than the surrounding air. However, they are still very effective in extracting heat from within spaces and have a cooling effect on us. 

This happens because human skin always has a small amount of external moisture. When exposed to a breeze, this moisture quickly evaporates, cooling your skin in a process called evaporative cooling. 

“At Senderos, we try to make use of natural methods like wind cooling in tandem with smart application of radiant heat as much as possible for two reasons. 

First, it maintains a connection to fresh air and nature throughout the home, which we think is part of the reason Costa Rica is a great place to live. And second, it helps make the home more cost effective by reducing the amount of air conditioning required.”

Innovation in Senderos | Radiant Cooling

One area that our team is working on in Senderos is the possibility of radiant cooling. Radiant heating has already existed for a long time through the existence of radiators, and more recently through radiant heating in floors, providing an upgraded form of less obtrusive heating. 

The same process could theoretically be used to offer radiant cooling. A cool thermal mass in the ceiling or walls would operate in the exact opposite form, drawing heat out of the objects close by. 

“There are a few considerations obviously, which is why you don’t have tons of radiant cooling already. You have to deal with humidity and condensation, and how you integrate that into a home’s design, but the use case has a lot of potential. 

Imagine a slightly more efficient way to cool down the home, where you don’t need to worry about ‘letting out the cold air’. And in fact, you could sit outside on your porch in the sun, and have it be as cool as sitting next to the ocean or a lake.”

Setting the Cutting Edge in the Tropics

There’s no one answer to heat management, because each home has its own design and unique environment. However, there are a number of key principles that can be applied to any home to improve its thermal profile. 

This is where the Senderos team is looking to help set the cutting edge in the tropics. Around the world, builders collaborate, share information, and test new designs and techniques to consistently improve collective building knowledge. 

This exchange of information isn’t as common in Central America and the tropics, though that’s changing with the launch of architectural and building institutes throughout Costa Rica. 

Working with cutting edge instruments, these programs focus on extensive data collection and testing on a wide variety of factors like the overall heat profile of a home, the tightness of its building envelope, its resistance to factors like wind, rain, and salt, and much more.

“We’ve already started these tests with the existing homes and designs throughout Senderos, especially with thermal imaging, and look forward to being a leading contributor to the body of knowledge about building in the tropics.” 

Come Experience It Yourself

We’re grateful to occupy the beautiful mountainside just inland of Tamarindo, one of the most exciting and interesting towns in Costa Rica. So it makes sense that we’d want to build the best homes possible, to truly make the most of this special part of the world. 

Thanks to Curtis for sitting down and giving us another look into the design, detail, and innovation that go into each home — from heat management to homeowner experience. 

If you’d like to visit Senderos and plan a tour, you can reach out to us at info@senderos-cr.com.