Coated article with IR reflecting layer and method of making same

1. An IG window unit including a coating supported by a glass substrate, the coating from the glass substrate outwardly comprising at least the following:

a dielectric layer of Si 3 N 4 ;

a high index layer having a refractive index of at least 2.1;

another dielectric layer comprising silicon nitride;

a layer comprising zinc oxide;

an infrared (IR) reflecting layer comprising silver on the glass substrate, located over and directly contacting the layer comprising zinc oxide, wherein the coating includes only one IR reflecting layer;

an overcoat comprising (i) a layer comprising tin oxide and (ii) a layer comprising silicon nitride located over and contacting the layer comprising tin oxide;

wherein the IG unit has an SHGC value of at least 0.65, a visible transmission of at least 70%, and an Energy Rating of at least 25;

wherein the coating does not contain any titanium oxide based layer located over the IR reflecting layer; and

wherein said glass substrate is an interior glass substrate, the IG unit further comprising an exterior glass substrate to be located adjacent an exterior of a building in which the IG unit is provided, wherein the coating is provided on a surface of the interior glass substrate facing a gap between the interior and exterior glass substrates, and wherein the IG is configured to have, as viewed from an exterior of the building, a reflective a* value of from about −4 to 0 and a reflective b* value of from about −1 to +2.5.

2. The IG unit of claim 1 , wherein the IG unit has an SHGC value of at least 0.68, a visible transmission of at least 74.5%, and an Energy Rating of at least 29.

3. The IG unit of claim 1 , wherein the coating further comprising a layer comprising Ni and Cr located over and directly contacting the IR reflecting layer comprising silver.

4. The IG unit of claim 1 , wherein the high index layer has a refractive index of at least 2.3.

5. The IG unit of claim 1 , wherein the high index layer has a refractive index of from 2.3 to 2.6.

6. The IG unit of claim 1 , wherein the high index layer is located between and directly contacting said dielectric layer of Si 3 N 4 and said another dielectric layer comprising silicon nitride.

7. The IG unit of claim 6 , wherein said dielectric layer of Si 3 N 4 is in direct contact with the glass substrate.

8. The IG unit of claim 6 , wherein said layer comprising zinc oxide is in direct contact with said another dielectric layer comprising silicon nitride.

9. An IG window unit including a coating supported by a glass substrate, the coating from the glass substrate outwardly comprising at least the following:

a dielectric layer of Si 3 N 4 ;

a high index layer having a refractive index of at least 2.1;

another dielectric layer comprising silicon nitride;

a layer comprising zinc oxide;

an infrared (IR) reflecting layer comprising silver on the glass substrate, located over and directly contacting the layer comprising zinc oxide, wherein the coating includes only one IR reflecting layer;

an overcoat comprising (i) a layer comprising tin oxide and (ii) a layer comprising silicon nitride located over and contacting the layer comprising tin oxide;

wherein the IG unit has an SHGC value of at least 0.65, a visible transmission of at least 70%, and an Energy Rating of at least 25;

wherein the coating does not contain any titanium oxide based layer located over the IR reflecting layer; and

wherein the IG unit is configured to have, as viewed from an exterior of a building, a reflective a* value of from about −4 to 0 and a reflective b* value of from about −1 to +2.5.

10. The IG unit of claim 9 , wherein the IG unit is configured to have an SHGC value of at least 0.68, a visible transmission of at least 74.5%, and an Energy Rating of at least 29.

11. The IG unit of claim 9 , wherein the glass substrate is an interior glass substrate of the IG unit.

12. The IG unit of claim 9 , wherein the coating further comprising a layer comprising Ni and Cr located over and directly contacting the IR reflecting layer comprising silver.

13. The IG unit of claim 9 , wherein the high index layer has a refractive index of at least 2.3.

14. The IG unit of claim 9 , wherein the high index layer has a refractive index of from 2.3 to 2.6.

15. The IG unit of claim 9 , wherein the high index layer is located between and directly contacting said dielectric layer of Si 3 N 4 and said another dielectric layer comprising silicon nitride.

16. The IG unit of claim 9 , wherein said dielectric layer comprising silicon nitride is in direct contact with the glass substrate.

17. The IG unit of claim 9 , wherein said layer comprising zinc oxide is in direct contact with said another dielectric layer comprising silicon nitride.

18. An IG window unit including a coating supported by a glass substrate, the coating from the glass substrate outwardly comprising at least the following:

a dielectric layer of Si 3 N 4 ;

a high index layer having a refractive index of at least 2.1;

another dielectric layer comprising silicon nitride;

a layer comprising zinc oxide;

an infrared (IR) reflecting layer comprising silver on the glass substrate, located over and directly contacting the layer comprising zinc oxide, wherein the coating includes only one IR reflecting layer;

an overcoat comprising (i) a layer comprising tin oxide and (ii) a layer comprising silicon nitride located over and contacting the layer comprising tin oxide;

wherein the IG unit has a visible transmission of at least 70%;

wherein the coating does not contain any titanium oxide based layer located over the IR reflecting layer; and

wherein the IG unit is configured to have, as viewed from an exterior of a building, a reflective a* value of from about −4 to 0 and a reflective b* value of from about −1 to +2.5.