Why does changing the SHGC value does not make difference in the result


I was asked to do an Indoor Comfort Analysis. I am trying to use different SHGC values in order to decide the best strategy. I did both PMV and Adaptative simulations. When the material on the glass is OFF there is lower heat in the areas. But when I add the SHGC trhough eponstructions the heat is higher and it doesn´t matter the value I add. I trying that the calculate the difference of heat between glass with 0.55 SHGC and 0.80 SHGC.

The issue hee is that I don´t know if I am doing it correctly or not. Because as far as I know I am following the correct method but the result is the same.

Here find attached the Rhino model and both the PMV and Adaptative comfort on grasshopper.

PTule Indoor PMV comfort.3dm (308.2 KB)
Indoor_PMV_Comfort.gh (649.7 KB) Indoor_Adaptive_Comfort 6.gh (655.2 KB)


  1. I see that your initial room brep has holes in it where the windows are, but this needs to be a closed volume:

  2. I see you are using SolveAdjacencies with airwalls but there is only one zone - is this intentional?

  3. I think you need to give your construction a name, and I believe you need to also delete the layer inputs that don’t receive data:

  4. The SHGC input should be a fraction between 0 and 1 but you have entered 5.5 - I assume you mean 0.55:

  5. The VT is a required input is required. For early-stage, low-resolution simulations I often just set it to the same as the SHGC, but ideally you would check the manufacturer’s datasheets:

  6. The EPWindowShades component finds the windows in a model and applies shades parametrically to these windows. Therefore, your addHBGlazing should come before this:

  7. The EPWindowShades component asks for several numeric inputs (depth, numOfShd, distBetween) but you are inputting breps:

    This is how the component is intended to be used:

    …but what you seem to be wanting to do is to input your shading geometries from Rhino directly, so why not just do this:

  8. You have set natural ventilation to occur every time the indoor and outdoor temperatures are between 0 and 50 degrees, but realistically no one opens windows at 0 degrees:

    Here is a more realistic setup that I have seen as an example in the EnergyPlus manual:

    This means: “windows are opened when the indoor temperature is above 24C, but only if the outdoor temperature is at least 1C cooler”

With all those changes, here is the output I’m getting:

When I change the SHGC to 0.8, I get this:

As you can see, the results are quite similar. This is because the space is air-conditioned; in the SHGC 0.8 variation, you are probably just using more energy to keep the room temperature acceptable. If you are interested in comfort, I suggest either using comfort maps, or, switching off the AC for the simulation to see how well your space performance in passive mode:

SHGC 0.55:

SHGC 0.80:

You might want to extract a meta-parameter, e.g. percentage of time where PMV>1. This is 16% for SHGC 0.55 and 19% for SHGC 0.80.

Indoor_PMV_Comfort.gh (663.4 KB)


Wow!! Thank you so much, I am an amateur with this softwares, I´ve been struggling with this simulation for a week and always having the same result. I did try though the shades as a context, but still my mistakes where in other areas I did not knew how to solve. I started from the example of Hydra, and as you can see I didn´t need the SolveAdjacencies that where in the original model.

I´ve been monday to sunday learning this amazing software, and the forum is quite helpful, thabk you again Max!!!

1 Like

Hi @MaxMarschall
do you know that EP Window Shades can also be used in the Honeybee Plus algorithms? Or the equivalent of this component is available in Honey Plus! I did not see .

@Aliarch, I have never used the Plus algorithms but my understanding is that these are becoming superseded by the Ladybug Tools V1 releases.

In V1, the equivalent component is HB Louver Shades, and there is also HB Extruded Border Shades:

thank you so much @MaxMarschall . :ok_hand: :ok_hand: :ok_hand: