How to use Solar PV and battery to comply to SANS 10400XA ed2, Opportunity

I am an Architectural professional with 8 years Solar industry experience and 12 years experience in applying SANS 10400 XA 1 and SANS 204, and recently SANS 10400 XA ed 2 (2021). Fact: New Houses (not limited to new houses though - many occupancy categories) must comply to the above mentioned regulations which require architectural professionals to often specify very expensive Glass and insulation materials in new houses just to comply to the energy efficiency in buildings regulations mentioned above. However very few Architectural professionals, home owners and Solar professionals know that you can comply to SANS 10400 XA ed 2 by means of substituting expensive Glass(fenestration) for a rather more affordable Solar PV and battery back-up system, which Satisfy regulation XA1, point 4.2 in full by demonstrating that a new house comply to the regulation thru its performance being less or equal to the MAX annual energy demand and Energy consumption listed in Table 1 & table 2 of the regulation.
The question must be asked to the owner and his/her Arch professional on why they should be paying As example, say R 500 000 for a double glazed glass installation in their dream house, when they could install a good performance single glazed glass for half of the cost, and rather use the remaining budget to invest in a solar and battery back up system that would

  1. make them compliant to all energy efficiency regulations,
  2. Insure energy security and cut out Load shedding completely,
  3. Cut their projected energy costs by an average of 70%.
    Its a no- brainer. But very little professionals know and implement this option, which is by far the most feasible, realistic, cost effective and most compliant solution available anywhere in the world.
    It is a missed opportunity for many Solar professionals quoting on new houses where Solar is planned into the design because 80% of Arch professionals out there are afraid to spec Solar on plans because they don’t understand it. However mentioning this to your client will be the nail in the coffin which secures you the deal. If you require more information on this, feel free to contact me for more information regarding this awesome angle and opportunity to truly save your client from worst case scenario solutions that wont benefit them at all.

Mmm, I’m rather interested to explore this.

Want to build a sunny north-facing area with lots of windows/steel frame construction over a slab and not be limited to the regulation ito windows East and North. Nothing West.

Currently want to call it a “braai room” and later make it a “bedroom”. :rofl:

I recently spoke to an architect that informed me that a braai room, or enclosed patio does not have to comply to the same fenestration requirements as the rest of the house. I am not sure if this is entirely true, but you might be in luck if you call it a patio/braai room. Perhaps @Zinnia can enlighten us?

If you want to have a bed in your braai room, that is your own business.

These things tend to be stated in overly complicated language and jargon. I had a look at some regs, and they are pretty daunting.
But, being in a technical field, I usually have a ballpark idea of the materials volume and design limitations I will face on a project. This comes with experience.

I presume in your own field, you have also developed this ability.
For the forum’s benefit, have you a better way of stating things in terms that people can get their heads around?

As a rule of thumb, or even a few rules of thumb like:

1m2 too much North facing window opening, needs X amount of solar generation to offset it?
Or similar?

Some guidelines that would be good practice even if a builder wasn’t faced with reams of bureaucracy.

It is true.
Gets even easier if the house and braairoom/patio one wants to enclose, are separate from the main dwelling, no interleading door.

BUT … the minuc here in Cpt, our area specifically, are not bamboozled easily. Like in speaking to them, they see one coming a mile away … based on previous challenges I needed them to help me with when they “argued” for things in my favor.

The R&Rs, T&Cs, man, they get seriously complicated when building today. I get it though, it saves a ton over the lifetime of the building.

So I’m intrigued with the idea of using solar to offset some of the window’s R/values … not sure if it will be as awesome as one would want it to be. Wonder what happens if you get approval to build and install the solar “saving” offset, only to remove the solar system in a few years for whatever reason?

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Yup. My architect (on the last modification) also confirmed it. Sunroom… no excessive need for insulation. But I was adding a bathroom, so the ceiling had to have the good stuff on top. No dodging it.

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It is the window area I’m after. Want the views.
The roof will have the required best stuff, no need to get it from above in Cpt summer too.
As ex-Valies … ons like die middag noorde sonnetjie wat inskyn.

And a braai needs a bathroom too, want to wash your hands, have a wee, maybe need a shower if one bought very wet wood? Don’t want to bring that smell into the house see. :rofl:

For those not in the know:
When one builds today, your sqm floor allows what % of total window/door openings you can have. I’m hampered on 55 sqm by ±18% of that in openings. Want the entire north and east walls windows.

And if you want west-facing windows, the “penalty” gets bigger unless you go double-glazing.

One does not want to build in Blouberg today with a view of the ocean. Friends of us have a “penthouse” there … the heat-bocking curtains come down late afternoon, the lights too(!) … when the sun sets. Blistering hot inside too, aircon runs flat out and loses the battle … sun right in your face, and bugger sunglasses, they are useless.

That is if you are not blown off the balcony when braaiing. Silly vaalies who want to go and spend Dec there. :rofl:

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Guys. The SANS 10400 XA (previous and existing is a “deemed to satisfy” regulation. Thus - the solutions or “requirements” there-in are meant to be deemed to satisfy and are by no means “a best practice standard”, its the worst possible solution to comply to as a regulation. But in this regulation they offer you more than 1 way to satisfy the regulation and that is where the ball gets dropped. Because you can either satisfy the regulation by complying to it - which is the limitations on western elevations, limitations on window sizes, building orientation needing to be east west etc, or as I stated by proving that you comply to the annual energy demand and consumption allowed by means of calculation or rational design (solar - Its a simple calculation and I am willing to help), or by fenestration calculations proofing that you are installing fenestration which are equal or better than the allowed values stipulated in the regulation (also a rational design, but based on fenestration to satisfy the regulation, and lastly by using thermal calculation software to proof that a reference building with similar size performs according to the regulations. The last option cost more to do if you have a dumb architect, but are the easiest and thus least efficient to the benifit of the home owner, because most of these solutions would just come down to “its okay to install single glazed glass in this home” even on those extreme west sunset facades, because the make a million assumptions - like curtains, paint color of walls, ceiling thickness, floorcovering -carpets are king!, and even furniture and human heat radiance to come to a beneficial conclusion, which in my opinion renders the whole regulation semi pointless, cause anybody can thus pass if their wallet allows for these calculation software companies to make them pass. You must ask the question - what is the purpose of these regulations?? It is actually to reduce our carbon footprint, - so we can limit greenhouse gasses, as is the international standard goal. So by cheating you are not achieving anything, and by installing most expensive glass you are wasting money which could have subsidized your solar system, and actually delivered to the purpose of the rule. Eish…its a no brainer.
Thus, if you have a clever or at least energy conscious architectural professional (no need to be an architect, just an experienced energy efficiency architectural professional) you will get better solutions that the deemed to satisfy solutions - which unfortunately includes the double-glazed window solutions and minimum western elevation facades etc. AS someone stated above, it comes down to common sense if you intend to do a double volume glass facade facing west…especially in the western cape without any shading devices to offset that glare -( we refer to that in glazing as the SHGC values of the glass which basically refers to the ability of the glass to control the heat-gain thru your glass and the effect it has on a room) I’ve seen houses in Pinicale Golf estate facing west with those huge windows, and man oh man, no solar can save them, but that comes down to BAD architectural planning. Nothing can be done about that if the owner isoblivious to our times and not clued up on where is north and south, nobody will save him from that disaster. However, what I am referring to in my post was merely the position and opportunity to save your clients huge heaps of money on un-necessary expensive glass expenditure due to their arch professional not being energy efficient orientated, and merely interested in getting the plan approved.
Its a waste of money, and I can tell you now, once you gain experience in this field, you will find that by virtue of past MV readings gathered you will be quite the expert in working out the simple calculation on what a certain house size will be allowed to use per day via max demand and consumption, and this calculation alone will secure you the solar deal if you look into it.
ANyhow, my fingers are now feeling dumb and Im gonna take a break. Feel free to contact me for a in depth explanation that might just open a total new market posibility!

you shoul read the regulation and what it says there will be your answer (sans 10400 XA ed 2 2021). Certain areas are excluded, yes, but when attached to the house, it forms part of the building envelope and thus cannot be excluded according to my understanding of the regulation. You can however exclude Garages and store rooms, but a braai room is a different situation, because again we must go back to the purpose of the regulation, which is to reduce our carbon footprint. How do we do that? and WHy?
So if you have a cold braai room in the winter you might light a fire in the braai (thats actually increasing your carbon footprint by the way, because you are burning wood) or light a fire place, or even worse, you dare to switch on your electrical heater or Aircon on max temperature. All of these theoretically will increase your energy usage, which means you burn more coal, which means more carbon into atmosphere, and the rational is that if you have cheap glass, it means that the heat will alwys try and replace the cold, thus heat will escape thru the glass and thry to heat up the outside. THe opposite will happen int the summer offcourse, where cold air from aircons will be absorbed thru glass by heat from outside. this leads to aircons/or heaters running for longer to try and recover heat/cold loss thru cheap glass. “unless you install double glazed glass as example” or install solar and dont give a sh!!t about how long you use your aircon because its powered by sun and battery.
Point is…Thus even a braai room have a definite effect on the energy efficiency of a building, and should not be excluded from your energy calculations. You should however look at the definition of a habitable room in SANS 10400 part A which says" - quoted:
habitable room
room used or designed, erected, adapted or intended to be used by persons for sleeping in, living
in, the preparation or consumption of food or drink, the transaction of business, the rendering of
professional services, the manufacture, processing or sale of goods, the performance of work, the
gathering together of persons or for recreational purposes"
Now according to this, your braai room is definitely not excluded from your calculations and you should educate your architect about it, or ask him to spec a few panels to your system and do a rational design!.

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the calculation is simple - we have differnet energy zones (found in SANS 10400XA ed 2), and as example I can say that to calculate your max energy consumption (table 1 of regulation)in for instance in a place like Krugersdorp which falls under energy ZOne 1, the calculation will be as follows for a 200m² house:
Zone 1 house(H4) = 95 kWh/m²/a (1kWh = 1unit of electricity thus I refer to units going forward)
MAX consumption = 95 units/m²/a
= 95 x 200m²
= 19000 units/annum.
Thus max units allowed to consume for a 200m² per day = 19000/365 days = 52.05 Units per day
COnclusion: a 200m² in Krugersdorp (zone 1) should not/may not consume more than 52 units per day or else this house would not comply to the deemed to satisfy regulations according to SANS 10400 PART XA.
MAX demand for 200m² house in ZONe 1 (Krugersdorp)(table 2 of regulation) THis means max load this house may put on the grid at anytime during 365 days (lets just say forever)
MAX demand Zone 1 = 58 VA/m²
Thus max load = 58VAx200m²
= 11600VA
= 11.6kVA load
(keep in mind these figures are max alowable - if your client goes over this - he needs to put up solar to comply - but if he is under, then youve just proofed that he does not need any special glass to comply. but it then needs to be measured and stated, otherwise - spec a 5kW solar system and this will limit his max load to inverter size in general, except for those backyard welders, and consumption will reduce on max allowed by apprx 30 units a day.

Thus providing a 200m²

I always thought that it’s really smart to have standards compiled using public funds, and then make them completely inaccessible to the general public (that paid for them). /s

Is there anywhere I can get hold of it without paying?

not good news unfortunately. only if you visit maybe an architectural professional, or some engineers will have them. I have them but I cannot give them out because of the copyright protection. Thus its there for free viewing to my clients and for my own use, lol but putting something like that on a platform like this would really really make them mad. Better thing to do is to google a guide to explain SANS 10400 XA, and in such guides you will have most of the relevant information including tables and zones to look at

Thanks for that explanation.
I do understand it.
My comments are:
The greater the area of the house, the more energy is allowed.
A 200m2 house is large, but limiting the lecky bill to 1560kWh/month for a household is very doable and probably very done. ( Especially with load shedding).

Is this an actual measured amount post-build, or is it just theoretical pre-build numbers that have lost touch with reality?

I am on 525kWh / month :slight_smile:
Main house with myself and wife and 1 flatlet with 1 tenant, we do however have a solar water heater which also helps to bring the consumption down.

This is a pre build max allowed to use as reference, but in a post build scenario, if you measure your true consumption (without taking load shedding into account) you will be able to determine if you are over or under. However if you have a client who are slightly interested in Solar, this is an angle to convince them that the solar will reduce their demand and consumption even more. I would even use the demand calculation to proof to the owner what the max size inverter is that they are "legally allowed " to install in a certain m² house, which means you will never over design a system.
To be honest, if you work out the max allowed consumption and demand wise - new home owners will pass SANS XA on these calculations alone since they are so lenient as MR. PJJ mentioned. BUt the way these regulations are structured are always with worst case scenario in mind, because Mr. PJJ might have a good deal with consumption because of his current household dynamics, but who is to say that the next person who buys his house does not rent it out to a family of 8, which would have a very different Demand and consumption profile

Can you post the calculation values based on your consumption…?

how big is the house and where is it situated

each building type, differs in values, aswell as in which energy zone it is situated. As example house in energy zone 1 (gauteng) will have a different calculation than a house in Mosselbay (energy zone 4)

So my question is more general… how is it calculated so general users can do the work for the own context. It is to late for me… I have made my last purchase in SA :wink:

Is there on line tool for example?