Nobody wants to pay more than they should. That is why it is important to keep up to date with what things should be costing you.
This blog is here to help you find out if your HVAC system is costing you too much – because it probably is.
What is an HVAC system?
Before I go into why your HVAC might be costing you too much, I will just briefly recap what your HVAC system is.
A heating, ventilation, and air conditioning (HVAC) system is the system that regulates the thermal comfort and indoor air quality (IAQ) components of indoor environmental quality (IEQ) in a building or vehicle. There are a lot of system configurations and components available, generally falling under the broad categories of all-air or air-and-water systems.
HVAC systems are essential for maintaining the comfort, health, and safety of occupants.
How much do HVAC systems cost?
The second point to discuss is if the cost is worth considering; the answer to this is simple: without a doubt.
HVAC’s can account for up to 40 % of a building’s energy consumption. Moreover, HVAC systems require regular maintenance to function correctly. Together, energetic use and maintenance costs of HVAC, therefore, comprise a significant portion of the mechanical running costs of any given building.
Also, the initial building cost of the HVAC in large buildings can be substantial, and highly influential in building design.Different system configurations and components can differ vastly in their initial price and space usage.
However, the primary concern regarding how much your HVAC system is costing you is not something as easily quantifiable as mechanical running costs, or the first cost of installation. If you have an HVAC system that is not providing good IAQ and thermal comfort, it could be costing you enormously in a more insidious way. I’ll get to this below.
Evidently, the cost of HVAC systems is a paramount concern and can make a world of difference to a company’s profitability in the long term.
Why your HVAC system is probably costing you too much
Now that you know what your HVAC does, and why it is financially significant, I’ll get to why it probably costs you too much.
This comes down to a simple issue. You may still be using a conventional all-air system, such as a variable air volume (VAV) system, rather than upgrading to a modern air-and-water system such as a dedicated outdoor air system (DOAS) combined with a radiant cooling system.
If you have not upgraded, then your HVAC system is costing you too much due to these three reasons:
1. Energy Efficiency
First off, there is the issue of energy efficiency. I have covered this in part in previous blogs, but primarily, studies over the last twenty years or so have shown accumulating evidence that “DOAS + Radiant” systems are much more energy efficient than any conventional HVAC. The improvement ranges depending on some factors but is usually somewhere in the range of 10 – 50 %. Even at the bottom end of this spectrum, 10 % energy savings can amount to substantial differences in energy consumption in the long term.
One recent assessment which compared a variable refrigerant flow (VRF) to a radiant system, found that while the initial cost of the radiant system was higher, the 15 % better energy efficiency of the radiant system would lead to a return on investment (ROI) period of just over three years. After the three years, the next twelve (assuming a lifecycle of 15 years) would incur savings into the millions.
2. Initial Cost and Maintenance
The initial cost of installation (or retrofitting) for a “DOAS + Radiant” is comparable to traditional systems, if not cheaper. A recent assessment of a “DOAS + Radiant” system compared to a VAV system by Sastry and Rumsey (2014) showed that general savings offered by a “DOAS + Radiant” compared to a VAV system were substantial, but that even the first cost of a “DOAS + Radiant” system is lower in comparison.
Moreover, the running costs for maintenance are much lower for “DOAS + Radiant” systems compared to traditional all-air systems. This is because of fewer air handling units (AHU) in the space, and largely reduced ducting and plenum space that requires cleaning. All-air systems that recirculate air will also need to clean and replace air filters more often.
3. The Costs of Poor IEQ
As I said above, the area that could be responsible for the largest proportion of inflated costs for your HVAC system is how it regulates IEQ.
“DOAS + Radiant” systems decouple the control of sensible (heat) and latent (moisture) energy. This allows them to more accurately, precisely, and efficiently control temperature and relative humidity within the occupied space. As I have covered in previous blogs, “DOAS + Radiant” systems also regulate an extra, and vital, component of the thermal environment that people perceive: the mean radiant temperature (MRT). “DOAS + Radiant” therefore regulate thermal comfort better than all-air systems.
Furthermore, DOAS are designed to provide proper ventilation to the occupied space at a lower flow rate and volume compared to traditional VAV systems. This helps continuously meet building code ventilation requirements and thus maintain good IAQ. On top of that, DOAS by definition provides 100 % fresh, outdoor air into the occupied space, which eliminates problems with recirculating air (and potentially recirculating and spreading contaminants such as allergens or toxic pollutants such as high carbon dioxide concentrations).
Overall, “DOAS + Radiant” systems provide far better regulation of IEQ than conventional all-air systems (particularly in difficult climates such as hot, humid zones). This is critical becauselower IEQ has been shown to reduce mental acuity, thereby lowering performance. Reduced IEQ can also lead to ‘sick building syndrome,’ where occupants become sick with a broad range of symptoms. The benefits of good IEQ are therefore realized as healthy workers, at work more often, being more productive. Indeed, Fisk et al. (2011) estimated the cost-benefit of improved IEQ to be approximately US$ 20 billion annually in the US alone.
Essentially, your HVAC system could be costing you far more than any running costs or initial cost assessment might show, simply through lost productivity and absenteeism. Put simply, if you are using a conventional system that does not regulate IEQ very well, you are at a massive financial disadvantage compared to competitors that optimize the working environment to get the best performance out of employees.
The marketplace is not getting any less competitive. To make it, you have to ensure that every aspect of your yearly turnover is scrutinized and optimized. Often, it can be difficult to isolate what is costing you too much, and where to make changes to enhance profitability.
In that regard, it is easy to overlook the HVAC because you may be blinded by the necessity of comfort. Because comfort is vital, you’ll pay anything for it. But that does not have to be the case. There is a way to not only improve IEQ but also to cut costs while doing so: “DOAS + Radiant” systems provide enhanced comfort, at lower costs.
Studies have shown that even in cases where the initial cost of installation or retrofitting is high, the ROI is usually less than three years. After that, the system will start amounting to significant savings. For equipment that typically has a lifespan of over fifteen years, that gives you at least twelve years of savings, and enhanced profitability.
As a final note, the value of the improved energy efficiency of a “DOAS + Radiant” system goes beyond the financial advantages. International building codes are increasingly incorporating codes for sustainability in the legislation. In an earlier article, I spoke about Singapore, the independent Asian city-state.
They have already mandated ‘green’ technology, and are at the forefront of business commerce. It is just a matter of time before other countries (especially in asia where pollution is a huge problem) follow suit, and begin expecting buildings to become more environmentally friendly. Therefore, “DOAS + Radiant” systems, therefore, provide an opportunity to not only save money but also to meet the growing demand for sustainability.