ᐅ Is the electricity consumption and procedure for screed drying typical?

Hi everyone,

I’m building with solid construction, and according to the site manager, a construction dryer is needed for the screed drying. So, for the past week, a 15 kW (kilowatt) heater has been running continuously, heating about 270 sqm (2,900 sq ft) at a supply temperature of 35°C (95°F). According to the protocol, you should start at 25°C (77°F), but nobody seems to care.

There is dripping from the walls, and the windows are always wet, like in a sauna.
Will this get better? At some point, all the moisture has to come out, right?
I ventilate twice a day, sometimes even three times, and always remove visible drops.
At 35°C (95°F), the energy consumption is 200 kWh per day. I calculated that over the planned 3 weeks, this will be over 4,000 kWh.
Does this sound about right, or could there be something wrong with the heater?

Moisture is also coming down from above through the precast ceilings—is this normal?
Unfortunately, my site manager is not very proactive, so I’m looking for advice here.

Best regards,
Felix

Will the moisture improve over time? Yes, typically after 4-8 weeks, depending on the weather, heating, and ventilation. Please keep in mind that there are thousands of liters of moisture inside the building, and only a tiny fraction of it is removed during each ventilation cycle.

Regarding heating: Usually, this is done using the built-in underfloor heating system, which often follows specific schedules with daily temperature increases. This was the case for us.

Aloha_Lars

Yes, sorry, of course the underfloor heating will be set to zero for me. However, it is a 20 kW heating unit with a consumption of 200 kWh per day for 270 m² (2900 ft²) of heated floor area. Does that fit? It seems very high to me. In the end, heating will cost me around €2,000.

medow1982 schrieb:

But it’s a 20KV heating unit.

20,000 volts? Or do you mean 20kW – which would be a maximum of 480kWh daily at full load.

So yes, the high consumption is plausible and could easily be twice as much.

medow1982 schrieb:

So, for one week now, about 270sqm (2,900 sqft) have been constantly heated with a 15KV heating unit at a flow temperature of 35 degrees Celsius (95°F). The protocol says to start at 25 degrees Celsius (77°F), but nobody pays attention to that.

Your expert should step in immediately. There are heating-up protocols for this (even if they’re not really meaningful today and I would dry it the same way myself).
By the way, that would be a 15kW heating unit, which could draw up to 360kWh per day. Do you have two units running?

medow1982 schrieb:

There’s dripping from the walls and the windows are always wet like in a sauna.
Will this improve? Eventually the moisture has to get out, right?

After one week, that is still completely normal.

medow1982 schrieb:

I calculated that I’ll be over 4000kWh for the planned 3 weeks.

That’s also plausible for such a large building.

medow1982 schrieb:

for the planned 3 weeks.

What kind of screed is that? What type of heating is being done? Functional heating and/or drying to readiness?

It is a single 20 kW unit, and functional heating has been running for one week with a supply temperature of 35°C (95°F). I know it should have started at 25°C (77°F), but in my case, it began at 35°C (95°F). The site manager says the screed company is monitoring everything. It is a CA screed. I thought the heating engineer would come daily, but no luck—he will probably only come when the temperature is increased.

medow1982 schrieb:

It is a single 20kW unit

OK. The consumption fits easily.

medow1982 schrieb:

Operating heating with a flow temperature of 35 degrees for one week.

That makes sense since it’s a new build and probably already well above the maximum temperature of the heat pump/floor heating system.

medow1982 schrieb:

The construction manager says the screeding company has everything under control.

If they guarantee the functionality in the end, you don’t need to worry. In fact, they also save costs with this warming-up approach.

medow1982 schrieb:

I thought the heating engineer would come daily, but no, he’ll probably only come when the temperature is increased.

He won’t come at all anymore. And assume that the temperature won’t be raised either (why should it?).

Summary: It might not comply with formal warming-up protocols, but those protocols date from times with much higher flow temperatures during heating operation. Consumption is normal, and moisture levels are too.