About the calculator

The expansion tank in the heating system is used to maintain the pressure in the system at a stable level. Our calculator allows you to estimate the volume of the expansion tank based on the volume of coolant or capacity of the equipment. Recall that the optimal pressure in heating systems of private homes – 1-2 bar. Theoretical basis of the calculation:

V_tank = (V_sum × e) / ((P_max - P_o) × (P_max + 1))

V_sum – heating System Volume;
e – volumetric coefficient of expansion;
P_max – maximum pressure;
P_o – initial pressure.

What expansion tank size do I need?

Enter the volume/power of your heating system.
Choose a type of coolant
Enter the coefficient of expansion of the fluid.
Enter the initial pressure.
Enter the maximum pressure.

Water expansion coefficient

°С	Coefficient of expansion	°С	Coefficient of expansion
0	0.00013	65	0.0198
10	0.00027	70	0.0227
20	0.00177	75	0.0258
30	0.00435	80	0.0290
40	0.00782	85	0.0324
50	0.0121	90	0.0359
55	0.0145	95	0.0396
60	0.0171	100	0.0434

Water-glycol mixture expansion coefficient

°С	Glycol, %
°С	0	10	20	30	40	50	70	90
0	0.00013	0.00320	0.00640	0.00960	0.01280	0.01600	0.02240	0.02880
10	0.00027	0.00340	0.00660	0.00980	0.01300	0.01620	0.02260	0.02900
20	0.00177	0.00480	0.00800	0.01120	0.01440	0.01760	0.02400	0.03040
30	0.00435	0.00740	0.01060	0.01380	0.01700	0.02020	0.02660	0.03300
40	0.00780	0.01090	0.01410	0.01730	0.02050	0.02370	0.03010	0.03650
50	0.01210	0.01510	0.01830	0.02150	0.02470	0.02790	0.03430	0.04070
60	0.01710	0.02010	0.02320	0.02630	0.02940	0.03250	0.03870	0.04490
70	0.02270	0.02580	0.02880	0.03180	0.03480	0.03780	0.04380	0.04980
80	0.02900	0.03200	0.03490	0.03780	0.04070	0.04360	0.04940	0.05520
90	0.03590	0.03890	0.04170	0.04450	0.04730	0.05010	0.05570	0.06130
100	0.04340	0.04650	0.04910	0.05170	0.05430	0.05690	0.06210	0.07290